Package 'adegenet'

Title: Exploratory Analysis of Genetic and Genomic Data
Description: Toolset for the exploration of genetic and genomic data. Adegenet provides formal (S4) classes for storing and handling various genetic data, including genetic markers with varying ploidy and hierarchical population structure ('genind' class), alleles counts by populations ('genpop'), and genome-wide SNP data ('genlight'). It also implements original multivariate methods (DAPC, sPCA), graphics, statistical tests, simulation tools, distance and similarity measures, and several spatial methods. A range of both empirical and simulated datasets is also provided to illustrate various methods.
Authors: Thibaut Jombart [aut] , Zhian N. Kamvar [aut, cre] , Caitlin Collins [ctb], Roman Lustrik [ctb], Marie-Pauline Beugin [ctb], Brian J. Knaus [ctb], Peter Solymos [ctb], Vladimir Mikryukov [ctb], Klaus Schliep [ctb], Tiago Maié [ctb], Libor Morkovsky [ctb], Ismail Ahmed [ctb], Anne Cori [ctb], Federico Calboli [ctb], RJ Ewing [ctb], Frédéric Michaud [ctb], Rebecca DeCamp [ctb], Alexandre Courtiol [ctb] , Lindsay V. Clark [ctb] , Pavel Dimens [ctb]
Maintainer: Zhian N. Kamvar <[email protected]>
License: GPL (>=2)
Version: 2.1.10
Built: 2024-08-20 04:20:02 UTC
Source: https://github.com/thibautjombart/adegenet

Help Index


Internal C routines

Description

These functions are internal C routines used in adegenet. Do not use them unless you know what you are doing.

Usage

.internal_C_routines

Format

An object of class NULL of length 0.

Author(s)

Thibaut Jombart


Compute and optimize a-score for Discriminant Analysis of Principal Components (DAPC)

Description

These functions are under development. Please email the author before using them for published results.

Usage

a.score(x, n.sim=10, ...)

optim.a.score(x, n.pca=1:ncol(x$tab), smart=TRUE, n=10, plot=TRUE,
              n.sim=10, n.da=length(levels(x$grp)), ...)

Arguments

x

a dapc object.

n.pca

a vector of integers indicating the number of axes retained in the Principal Component Analysis (PCA) steps of DAPC. nsim DAPC will be run for each value in n.pca, unless the smart approach is used (see details).

smart

a logical indicating whether a smart, less computer-intensive approach should be used (TRUE, default) or not (FALSE). See details section.

n

an integer indicating the numbers of values spanning the range of n.pca to be used in the smart approach.

plot

a logical indicating whether the results should be displayed graphically (TRUE, default) or not (FALSE).

n.sim

an integer indicating the number of simulations to be performed for each number of retained PC.

n.da

an integer indicating the number of axes retained in the Discriminant Analysis step.

...

further arguments passed to other methods; currently unused..

Details

The Discriminant Analysis of Principal Components seeks a reduced space inside which observations are best discriminated into pre-defined groups. One way to assess the quality of the discrimination is looking at re-assignment of individuals to their prior group, successful re-assignment being a sign of strong discrimination.

However, when the original space is very large, ad hoc solutions can be found, which discriminate very well the sampled individuals but would perform poorly on new samples. In such a case, DAPC re-assignment would be high even for randomly chosen clusters. The a-score measures this bias. It is computed as (Pt-Pr), where Pt is the reassignment probability using the true cluster, and Pr is the reassignment probability for randomly permuted clusters. A a-score close to one is a sign that the DAPC solution is both strongly discriminating and stable, while low values (toward 0 or lower) indicate either weak discrimination or instability of the results.

The a-score can serve as a criterion for choosing the optimal number of PCs in the PCA step of DAPC, i.e. the number of PC maximizing the a-score. Two procedures are implemented in optim.a.score. The smart procedure selects evenly distributed number of PCs in a pre-defined range, compute the a-score for each, and then interpolate the results using splines, predicting an approximate optimal number of PCs. The other procedure (when smart is FALSE) performs the computations for all number of PCs request by the user. The 'optimal' number is then the one giving the highest mean a-score (computed over the groups).

Value

=== a.score ===
a.score returns a list with the following components:

tab

a matrix of a-scores with groups in columns and simulations in row.

pop.score

a vector giving the mean a-score for each population.

mean

the overall mean a-score.


=== optim.a.score ===
optima.score returns a list with the following components:

pop.score

a list giving the mean a-score of the populations for each number of retained PC (each element of the list corresponds to a number of retained PCs).

mean

a vector giving the overall mean a-score for each number of retained PCs.

pred

(only when smart is TRUE) the predictions of the spline, given in x and y coordinates.

best

the optimal number of PCs to be retained.

Author(s)

Thibaut Jombart [email protected]

References

Jombart T, Devillard S and Balloux F (2010) Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. BMC Genetics11:94. doi:10.1186/1471-2156-11-94

See Also

- find.clusters: to identify clusters without prior.

- dapc: the Discriminant Analysis of Principal Components (DAPC)


Accessors for adegenet objects

Description

An accessor is a function that allows to interact with slots of an object in a convenient way. Several accessors are available for genind or genpop objects. The operator "$" and "$<-" are used to access the slots, being equivalent to "@" and "@<-".

The operator "[" is a flexible way to subset data by individuals, populations, alleles, and loci. When using a matrix-like syntax, subsetting will apply to the dimensios of the @tab slot. In addition, specific arguments loc and pop can be used to indicate subsets of loci and populations. The argument drop is a logical indicating if alleles becoming non-polymorphic in a new dataset should be removed (default: FALSE). Examples:

  • "obj[i,j]" returns "obj" with a subset 'i' of individuals and 'j' of alleles.

  • "obj[1:10,]" returns an object with only the first 10 genotypes (if "obj" is a genind) or the first 10 populations (if "obj" is a genpop)

  • "obj[1:10, 5:10]" returns an object keeping the first 10 entities and the alleles 5 to 10.

  • "obj[loc=c(1,3)]" returns an object keeping only the 1st and 3rd loci, using locNames(obj) as reference; logicals, or named loci also work; this overrides other subsetting of alleles.

  • "obj[pop=2:4]" returns an object keeping only individuals from the populations 2, 3 and 4, using popNames(obj) as reference; logicals, or named populations also work; this overrides other subsetting of individuals.

  • "obj[i=1:2, drop=TRUE]" returns an object keeping only the first two individuals (or populations), dropping the alleles no longer present in the data.

The argument treatOther handles the treatment of objects in the @other slot (see details). The argument drop can be set to TRUE to drop alleles that are no longer represented in the subset.

Usage

nInd(x, ...)
nLoc(x, ...)
nAll(x, onlyObserved = FALSE, ...)
nPop(x, ...)
pop(x)
indNames(x, ...)
## S4 method for signature 'genind'
indNames(x, ...)
locNames(x, ...)
## S4 method for signature 'genind'
locNames(x, withAlleles=FALSE, ...)
## S4 method for signature 'genpop'
locNames(x, withAlleles=FALSE, ...)
popNames(x, ...)
## S4 method for signature 'genind'
popNames(x, ...)
popNames(x, ...)
## S4 method for signature 'genpop'
popNames(x, ...)
ploidy(x, ...)
## S4 method for signature 'genind'
ploidy(x, ...)
## S4 method for signature 'genpop'
ploidy(x, ...)
## S4 method for signature 'genind'
other(x, ...)
## S4 method for signature 'genpop'
other(x, ...)

Arguments

x

a genind or a genpop object.

onlyObserved

a logical indicating whether the allele count should also include the alleles with onlyObserved columns in the matrix. Defaults to FALSE, which will report only the observed alleles in the given population. onlyObserved = TRUE will be the equivalent of table(locFac(x)), but faster.

withAlleles

a logical indicating whether the result should be of the form [locus name].[allele name], instead of [locus name].

...

further arguments to be passed to other methods (currently not used).

Details

The "[" operator can treat elements in the @other slot as well. For instance, if obj@other$xy contains spatial coordinates, the obj[1:3, ]@other$xy will contain the spatial coordinates of the genotypes (or population) 1,2 and 3. This is handled through the argument treatOther, a logical defaulting to TRUE. If set to FALSE, the @other returned unmodified.

Note that only matrix-like, vector-like and lists can be proceeded in @other. Other kind of objects will issue a warning an be returned as they are, unless the argument quiet is left to TRUE, its default value.

The drop argument can be set to TRUE to retain only alleles that are present in the subset. To achieve better control of polymorphism of the data, see isPoly.

nAll() reflects the number of columns per locus present in the current gen object. If onlyObserved = TRUE, then the number of columns with at least one non-missing allele is shown.

Value

A genind or genpop object.

Methods

nInd

returns the number of individuals in the genind object

nLoc

returns the number of loci

nAll

returns the number of observed alleles in each locus

nPop

returns the number of populations

pop

returns a factor assigning individuals to populations.

pop<-

replacement method for the @pop slot of an object.

popNames

returns the names of populations.

popNames<-

sets the names of populations using a vector of length nPop(x).

indNames

returns the names of individuals.

indNames<-

sets the names of individuals using a vector of length nInd(x).

locNames

returns the names of markers and/or alleles.

locNames<-

sets the names of markers using a vector of length nLoc(x).

locFac

returns a factor that defines which locus each column of the @tab slot belongs to

ploidy

returns the ploidy of the data.

ploidy<-

sets the ploidy of the data using an integer.

alleles

returns the alleles of each locus.

alleles<-

sets the alleles of each locus using a list with one character vector for each locus.

other

returns the content of the @other slot (misc. information); returns NULL if the slot is onlyObserved or of length zero.

other<-

sets the content of the @other slot (misc. information); the provided value needs to be a list; it not, provided value will be stored within a list.

Author(s)

Thibaut Jombart [email protected]

Examples

data(nancycats)
nancycats
pop(nancycats) # get the populations
indNames(nancycats) # get the labels of individuals
locNames(nancycats) # get the labels of the loci
alleles(nancycats)  # get the alleles
nAll(nancycats)     # count the number of alleles

head(tab(nancycats)) # get allele counts

# get allele frequencies, replace NAs
head(tab(nancycats, freq = TRUE, NA.method = "mean")) 

# let's isolate populations 4 and 8
popNames(nancycats)
obj <- nancycats[pop=c(4, 8)]
obj
popNames(obj)
pop(obj)
nAll(obj, onlyObserved = TRUE) # count number of alleles among these two populations
nAll(obj) # count number of columns in the data
all(nAll(obj, onlyObserved = TRUE) == lengths(alleles(obj))) # will be FALSE since drop = FALSE
all(nAll(obj) == lengths(alleles(obj))) # will be FALSE since drop = FALSE

# let's isolate two markers, fca23 and fca90
locNames(nancycats)
obj <- nancycats[loc=c("fca23","fca90")]
obj
locNames(obj)

# illustrate pop
obj <- nancycats[sample(1:100, 10)]
pop(obj)
pop(obj) <- rep(c('b', 'a'), each = 5)
pop(obj)

# illustrate locNames
locNames(obj)
locNames(obj, withAlleles = TRUE)
locNames(obj)[1] <- "newLocus"
locNames(obj)
locNames(obj, withAlleles=TRUE)

# illustrate how 'other' slot is handled
data(sim2pop)
nInd(sim2pop)
other(sim2pop[1:6]) # xy is subsetted automatically
other(sim2pop[1:6, treatOther=FALSE]) # xy is left as is

Web servers for adegenet

Description

The function adegenetServer opens up a web page providing a simple user interface for some of the functionalities implemented in adegenet. These servers have been developed using the package shiny.

Currently available servers include:

  • DAPC: a server for the Discriminant Analysis of Principal Components (see ?dapc)

Usage

adegenetServer(what=c("DAPC"))

Arguments

what

a character string indicating which server to start; currently accepted values are: "DAPC"

Value

The function invisibly returns NULL.

Author(s)

Thibaut Jombart [email protected] Caitlin Collins

See Also

dapc

Examples

## Not run: 
## this opens a web page for DAPC
adegenetServer()

## End(Not run)

The adegenet package

Description

This package is devoted to the multivariate analysis of genetic markers data. These data can be codominant markers (e.g. microsatellites) or presence/absence data (e.g. AFLP), and have any level of ploidy. 'adegenet' defines three formal (S4) classes:
- genind: a class for data of individuals ("genind" stands for genotypes-individuals).
- genpop: a class for data of groups of individuals ("genpop" stands for genotypes-populations)
- genlight: a class for genome-wide SNP data

Details

For more information about these classes, type "class ? genind", "class ? genpop", or "?genlight".

Essential functionalities of the package are presented througout 4 tutorials, accessible using adegenetTutorial(which="name-below"):
- basics: introduction to the package.
- spca: multivariate analysis of spatial genetic patterns.
- dapc: population structure and group assignment using DAPC.
- genomics: introduction to the class genlight for the handling and analysis of genome-wide SNP data.

Note: In older versions of adegenet, these tutorials were avilable as vignettes, accessible through the function vignette("name-below", package="adegenet"):
- adegenet-basics.
- adegenet-spca.
- adegenet-dapc.
- adegenet-genomics.

Important functions are also summarized below.

=== IMPORTING DATA ===
= TO GENIND OBJECTS =
adegenet imports data to genind object from the following softwares:
- STRUCTURE: see read.structure
- GENETIX: see read.genetix
- FSTAT: see read.fstat
- Genepop: see read.genepop
To import data from any of these formats, you can also use the general function import2genind.

In addition, it can extract polymorphic sites from nucleotide and amino-acid alignments:
- DNA files: use read.dna from the ape package, and then extract SNPs from DNA alignments using DNAbin2genind.

- protein sequences alignments: polymorphic sites can be extracted from protein sequences alignments in alignment format (package seqinr, see as.alignment) using the function alignment2genind.

The function fasta2DNAbin allows for reading fasta files into DNAbin object with minimum RAM requirements.

It is also possible to read genotypes coded by character strings from a data.frame in which genotypes are in rows, markers in columns. For this, use df2genind. Note that df2genind can be used for any level of ploidy.

= TO GENLIGHT OBJECTS =
SNP data can be read from the following formats:
- PLINK: see function read.PLINK
- .snp (adegenet's own format): see function read.snp

SNP can also be extracted from aligned DNA sequences with the fasta format, using fasta2genlight

=== EXPORTING DATA ===
adegenet exports data from

Genotypes can also be recoded from a genind object into a data.frame of character strings, using any separator between alleles. This covers formats from many softwares like GENETIX or STRUCTURE. For this, see genind2df.

Also note that the pegas package imports genind objects using the function as.loci.

=== MANIPULATING DATA ===
Several functions allow one to manipulate genind or genpop objects
- genind2genpop: convert a genind object to a genpop
- seploc: creates one object per marker; for genlight objects, creates blocks of SNPs.
- seppop: creates one object per population
- - tab: access the allele data (counts or frequencies) of an object (genind and genpop)
- x[i,j]: create a new object keeping only genotypes (or populations) indexed by 'i' and the alleles indexed by 'j'.
- makefreq: returns a table of allelic frequencies from a genpop object.
- repool merges genoptypes from different gene pools into one single genind object.
- propTyped returns the proportion of available (typed) data, by individual, population, and/or locus.
- selPopSize subsets data, retaining only genotypes from a population whose sample size is above a given level.
- pop sets the population of a set of genotypes.

=== ANALYZING DATA ===
Several functions allow to use usual, and less usual analyses:
- HWE.test.genind: performs HWE test for all populations and loci combinations
- dist.genpop: computes 5 genetic distances among populations.
- monmonier: implementation of the Monmonier algorithm, used to seek genetic boundaries among individuals or populations. Optimized boundaries can be obtained using optimize.monmonier. Object of the class monmonier can be plotted and printed using the corresponding methods.
- spca: implements Jombart et al. (2008) spatial Principal Component Analysis
- global.rtest: implements Jombart et al. (2008) test for global spatial structures
- local.rtest: implements Jombart et al. (2008) test for local spatial structures
- propShared: computes the proportion of shared alleles in a set of genotypes (i.e. from a genind object)
- propTyped: function to investigate missing data in several ways
- scaleGen: generic method to scale genind or genpop before a principal component analysis
- Hs: computes the average expected heterozygosity by population in a genpop. Classically Used as a measure of genetic diversity.
- find.clusters and dapc: implement the Discriminant Analysis of Principal Component (DAPC, Jombart et al., 2010).
- seqTrack: implements the SeqTrack algorithm for recontructing transmission trees of pathogens (Jombart et al., 2010) .
glPca: implements PCA for genlight objects.
- gengraph: implements some simple graph-based clustering using genetic data. - snpposi.plot and snpposi.test: visualize the distribution of SNPs on a genetic sequence and test their randomness. - adegenetServer: opens up a web interface for some functionalities of the package (DAPC with cross validation and feature selection).

=== GRAPHICS ===
- colorplot: plots points with associated values for up to three variables represented by colors using the RGB system; useful for spatial mapping of principal components.
- loadingplot: plots loadings of variables. Useful for representing the contribution of alleles to a given principal component in a multivariate method.
- scatter.dapc: scatterplots for DAPC results.
- compoplot: plots membership probabilities from a DAPC object.

=== SIMULATING DATA ===
- hybridize: implements hybridization between two populations.
- haploGen: simulates genealogies of haplotypes, storing full genomes.
glSim: simulates simple genlight objects.

=== DATASETS ===
- H3N2: Seasonal influenza (H3N2) HA segment data.
- dapcIllus: Simulated data illustrating the DAPC.
- eHGDP: Extended HGDP-CEPH dataset.
- microbov: Microsatellites genotypes of 15 cattle breeds.
- nancycats: Microsatellites genotypes of 237 cats from 17 colonies of Nancy (France).
- rupica: Microsatellites genotypes of 335 chamois (Rupicapra rupicapra) from the Bauges mountains (France).
- sim2pop: Simulated genotypes of two georeferenced populations.
- spcaIllus: Simulated data illustrating the sPCA.

For more information, visit the adegenet website using the function adegenetWeb.

Tutorials are available via the command adegenetTutorial.

To cite adegenet, please use the reference given by citation("adegenet") (or see references below).

Author(s)

Thibaut Jombart <[email protected]>
Developers: Zhian N. Kamvar <[email protected]>, Caitlin Collins <[email protected]>, Ismail Ahmed <[email protected]>, Federico Calboli, Tobias Erik Reiners, Peter Solymos, Anne Cori,
Contributed datasets from: Katayoun Moazami-Goudarzi, Denis Laloë, Dominique Pontier, Daniel Maillard, Francois Balloux.

References

Jombart T. (2008) adegenet: a R package for the multivariate analysis of genetic markers Bioinformatics 24: 1403-1405. doi: 10.1093/bioinformatics/btn129

Jombart T. and Ahmed I. (2011) adegenet 1.3-1: new tools for the analysis of genome-wide SNP data. Bioinformatics. doi: 10.1093/bioinformatics/btr521

Jombart T, Devillard S and Balloux F (2010) Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. BMC Genetics 11:94. doi:10.1186/1471-2156-11-94

Jombart T, Eggo R, Dodd P, Balloux F (2010) Reconstructing disease outbreaks from genetic data: a graph approach. Heredity. doi: 10.1038/hdy.2010.78.

Jombart, T., Devillard, S., Dufour, A.-B. and Pontier, D. (2008) Revealing cryptic spatial patterns in genetic variability by a new multivariate method. Heredity, 101, 92–103.

See adegenet website: http://adegenet.r-forge.r-project.org/

Please post your questions on 'the adegenet forum': [email protected]

See Also

adegenet is related to several packages, in particular:
- ade4 for multivariate analysis
- pegas for population genetics tools
- ape for phylogenetics and DNA data handling
- seqinr for handling nucleic and proteic sequences
- shiny for R-based web interfaces


Functions to access online resources for adegenet

Description

These functions simply open websites or documents available online providing resources for adegenet.

Usage

adegenetWeb()

adegenetTutorial(
  which = c("basics", "spca", "dapc", "genomics", "strata", "snapclust")
)

adegenetIssues()

Arguments

which

a character string indicating which tutorial to open (see details)

Details

  • adegenetWeb opens adegenet's website

  • adegenetTutorial opens adegenet tutorials

  • adegenetIssues opens the issue page on github; this is used to report a bug or post a feature request.

Available tutorials are:

  • 'basics': general introduction to adegenet; covers basic data structures, import/export, handling, and a number of population genetics methods

  • 'spca': spatial genetic structures using the spatial Principal Component Analysis

  • 'dapc': population structure using the Discriminant Analysis of Principal Components

  • 'genomics': handling large genome-wide SNP data using adegenet

  • 'strata': introduction to hierarchical population structure in adegenet

  • 'snapclust': introduction to fast maximum-likelihood genetic clustering using snapclust


Compute Akaike Information Criterion (AIC) for snapclust

Description

Do not use. We work on that stuff. Contact us if interested.

Usage

## S3 method for class 'snapclust'
AIC(object, ...)

Arguments

object

An object returned by the function snapclust.

...

Further arguments for compatibility with the AIC generic (currently not used).

Author(s)

Thibaut Jombart [email protected]

See Also

snapclust to generate clustering solutions.


Compute Akaike Information Criterion for small samples (AICc) for snapclust

Description

Do not use. We work on that stuff. Contact us if interested.

Usage

AICc(object, ...)

## S3 method for class 'snapclust'
AICc(object, ...)

Arguments

object

An object returned by the function snapclust.

...

Further arguments for compatibility with the AIC generic (currently not used).

Author(s)

Thibaut Jombart [email protected]

See Also

snapclust to generate clustering solutions.


Converting genind/genpop objects to other classes

Description

These S3 and S4 methods are used to coerce genind and genpop objects to matrix-like objects. In most cases, this is equivalent to calling the @tab slot. An exception to this is the convertion to ktab objects used in the ade4 package as inputs for K-tables methods (e.g. Multiple Coinertia Analysis).

Usage

as(object, Class)

Arguments

object

a genind or a genpop object.

Class

the name of the class to which the object should be coerced, for instance "data.frame" or "matrix".

Methods

coerce

from one object class to another using as(object,"Class"), where the object is of the old class and the returned object is of the new class "Class".

Author(s)

Thibaut Jombart [email protected]

Examples

## Not run: 
data(microbov)
x <- tab(microbov,NA.method="mean")
as(x[1:3],"data.frame")

## dudi functions attempt to convert their first argument
## to a data.frame; so they can be used on genind/genpop objects.
## perform a PCA
pca1 <- dudi.pca(x, scale=FALSE, scannf=FALSE)
pca1

x <- genind2genpop(microbov,miss="chi2")
x <- as(x,"ktab")
class(x)
## perform a STATIS analysis
statis1 <- statis(x, scannf=FALSE)
statis1
plot(statis1)


## End(Not run)

Conversion to class "genlight"

Description

The class genlight is a formal (S4) class for storing a genotypes of binary SNPs in a compact way, using a bit-level coding scheme. New instances of this class are best created using new; see the manpage of genlight for more information on this point.

As a shortcut, conversion methods can be used to convert various objects into a genlight object. Conversions can be achieved using S3-style (as.genlight(x)) or S4-style (as(x,"genlight") procedures. All of them call upon the constructor (new) of genlight objects.

Conversion is currently available from the following objects: - matrix of type integer/numeric - data.frame with integer/numeric data - list of vectors of integer/numeric type

Author(s)

Thibaut Jombart ([email protected])

See Also

Related class:
- SNPbin, for storing individual genotypes of binary SNPs

- genind

Examples

## Not run: 
## data to be converted
dat <- list(toto=c(1,1,0,0,2,2,1,2,NA), titi=c(NA,1,1,0,1,1,1,0,0), tata=c(NA,0,3, NA,1,1,1,0,0))

## using the constructor
x1 <- new("genlight", dat)
x1

## using 'as' methods
x2 <- as.genlight(dat)
x3 <- as(dat, "genlight")

identical(x1,x2)
identical(x1,x3)

## End(Not run)

Conversion to class "SNPbin"

Description

The class SNPbin is a formal (S4) class for storing a genotype of binary SNPs in a compact way, using a bit-level coding scheme. New instances of this class are best created using new; see the manpage of SNPbin for more information on this point.

As a shortcut, conversion methods can be used to convert various objects into a SNPbin object. Conversions can be achieved using S3-style (as.SNPbin(x)) or S4-style (as(x,"SNPbin") procedures. All of them call upon the constructor (new) of SNPbin objects.

Conversion is currently available from the following objects: - integer vectors - numeric vectors

Author(s)

Thibaut Jombart ([email protected])

See Also

Related class:
- SNPbin - genlight, for storing multiple binary SNP genotypes.

Examples

## Not run: 
## data to be converted
dat <- c(1,0,0,2,1,1,1,2,2,1,1,0,0,1)

## using the constructor
x1 <- new("SNPbin", dat)
x1

## using 'as' methods
x2 <- as.SNPbin(dat)
x3 <- as(dat, "SNPbin")

identical(x1,x2)
identical(x1,x3)

## End(Not run)

Auxiliary functions for adegenet

Description

adegenet implements a number of auxiliary procedures that might be of interest for users. These include graphical tools to translate variables (numeric or factors) onto a color scale, adding transparency to existing colors, pre-defined color palettes, extra functions to access documentation, and low-level treatment of character vectors.

These functions are mostly auxiliary procedures used internally in adegenet.

These items include:

  • num2col: translates a numeric vector into colors.

  • fac2col: translates a factor into colors.

  • any2col: translates a vector of type numeric, character or factor into colors.

  • transp: adds transparency to a vector of colors. Note that transparent colors are not supported on some graphical devices.

  • corner: adds text to a corner of a figure.

  • checkType: checks the type of markers being used in a function and issues an error if appropriate.

  • .rmspaces: remove peripheric spaces in a character string.

  • .genlab: generate labels in a correct alphanumeric ordering.

  • .readExt: read the extension of a given file.

Color palettes include:

  • bluepal: white -> dark blue

  • redpal: white -> dark red

  • greenpal: white -> dark green

  • greypal: white -> dark grey

  • flame: gold -> red

  • azur: gold -> blue

  • seasun: blue -> gold -> red

  • lightseasun: blue -> gold -> red (light variant)

  • deepseasun: blue -> gold -> red (deep variant)

  • spectral: red -> yellow -> blue (RColorBrewer variant)

  • wasp: gold -> brown -> black

  • funky: many colors

  • virid: adaptation of the viridis palette, from the viridis package.

  • hybridpal: reorder a color palette (virid by default) to display sharp contrast between the first two colors, and interpolated colors after; ideal for datasets where two parental populations are provided first, followed by various degrees of hybrids.

Usage

.genlab(base, n)
corner(text, posi="topleft",  inset=0.1, ...)
num2col(x, col.pal=heat.colors, reverse=FALSE,
        x.min=min(x,na.rm=TRUE), x.max=max(x,na.rm=TRUE),
        na.col="transparent")
fac2col(x, col.pal=funky, na.col="transparent", seed=NULL)
any2col(x, col.pal=seasun, na.col="transparent")
transp(col, alpha=.5)
hybridpal(col.pal = virid)

Arguments

base

a character string forming the base of the labels

n

the number of labels to generate

text

a character string to be added to the plot

posi

a character matching any combinations of "top/bottom" and "left/right".

inset

a vector of two numeric values (recycled if needed) indicating the inset, as a fraction of the plotting region.

...

further arguments to be passed to text

x

a numeric vector (for num2col) or a vector converted to a factor (for fac2col).

col.pal

a function generating colors according to a given palette.

reverse

a logical stating whether the palette should be inverted (TRUE), or not (FALSE, default).

x.min

the minimal value from which to start the color scale

x.max

the maximal value from which to start the color scale

na.col

the color to be used for missing values (NAs)

seed

a seed for R's random number generated, used to fix the random permutation of colors in the palette used; if NULL, no randomization is used and the colors are taken from the palette according to the ordering of the levels.

col

a vector of colors

alpha

a numeric value between 0 and 1 representing the alpha coefficient; 0: total transparency; 1: no transparency.

Value

For .genlab, a character vector of size "n". num2col and fac2col return a vector of colors. any2col returns a list with the following components: $col (a vector of colors), $leg.col (colors for the legend), and $leg.txt (text for the legend).

Author(s)

Thibaut Jombart [email protected]

See Also

The R package RColorBrewer, proposing a nice selection of color palettes. The viridis package, with many excellent palettes.

Examples

.genlab("Locus-",11)

## transparent colors using "transp"
plot(rnorm(1000), rnorm(1000), col=transp("blue",.3), pch=20, cex=4)


## numeric values to color using num2col
plot(1:100, col=num2col(1:100), pch=20, cex=4)
plot(1:100, col=num2col(1:100, col.pal=bluepal), pch=20, cex=4)
plot(1:100, col=num2col(1:100, col.pal=flame), pch=20, cex=4)
plot(1:100, col=num2col(1:100, col.pal=wasp), pch=20, cex=4)
plot(1:100, col=num2col(1:100, col.pal=azur,rev=TRUE), pch=20, cex=4)
plot(1:100, col=num2col(1:100, col.pal=spectral), pch=20, cex=4)
plot(1:100, col=num2col(1:100, col.pal=virid), pch=20, cex=4)

## factor as colors using fac2col
dat <- cbind(c(rnorm(50,8), rnorm(100), rnorm(150,3),
rnorm(50,10)),c(rnorm(50,1),rnorm(100),rnorm(150,3), rnorm(50,5)))
fac <- rep(letters[1:4], c(50,100,150,50))
plot(dat, col=fac2col(fac), pch=19, cex=4)
plot(dat, col=transp(fac2col(fac)), pch=19, cex=4)
plot(dat, col=transp(fac2col(fac,seed=2)), pch=19, cex=4)

## use of any2col
x <- factor(1:10)
col.info <- any2col(x, col.pal=funky)
plot(x, col=col.info$col, main="Use of any2col on a factor")
legend("bottomleft", fill=col.info$leg.col, legend=col.info$leg.txt, bg="white")

x <- 100:1
col.info <- any2col(x, col.pal=wasp)
barplot(x, col=col.info$col, main="Use of any2col on a numeric")
legend("bottomleft", fill=col.info$leg.col, legend=col.info$leg.txt, bg="white")

Compute Bayesian Information Criterion (BIC) for snapclust

Description

Do not use. We work on that stuff. Contact us if interested.

Usage

## S3 method for class 'snapclust'
BIC(object, ...)

Arguments

object

An object returned by the function snapclust.

...

Further arguments for compatibility with the BIC generic (currently not used).

Author(s)

Thibaut Jombart [email protected]

See Also

snapclust to generate clustering solutions.


Function to choose a connection network

Description

The function chooseCN is a simple interface to build a connection network (CN) from xy coordinates. The user chooses from 6 types of graph and one additional weighting scheme. chooseCN calls functions from appropriate packages, handles non-unique coordinates and returns a connection network either with classe nb or listw. For graph types 1-4, duplicated locations are not accepted and will issue an error.

Usage

chooseCN(
  xy,
  ask = TRUE,
  type = NULL,
  result.type = "nb",
  d1 = NULL,
  d2 = NULL,
  k = NULL,
  a = NULL,
  dmin = NULL,
  plot.nb = TRUE,
  edit.nb = FALSE,
  check.duplicates = TRUE
)

Arguments

xy

an matrix or data.frame with two columns for x and y coordinates.

ask

a logical stating whether graph should be chosen interactively (TRUE,default) or not (FALSE). Set to FALSE if type is provided.

type

an integer giving the type of graph (see details).

result.type

a character giving the class of the returned object. Either "nb" (default) or "listw", both from spdep package. See details.

d1

the minimum distance between any two neighbours. Used if type=5.

d2

the maximum distance between any two neighbours. Used if type=5. Can also be a character: "dmin" for the minimum distance so that each site has at least one connection, or "dmax" to have all sites connected (despite the later has no sense).

k

the number of neighbours per point. Used if type=6.

a

the exponent of the inverse distance matrix. Used if type=7.

dmin

the minimum distance between any two distinct points. Used to avoid infinite spatial proximities (defined as the inversed spatial distances). Used if type=7.

plot.nb

a logical stating whether the resulting graph should be plotted (TRUE, default) or not (FALSE).

edit.nb

a logical stating whether the resulting graph should be edited manually for corrections (TRUE) or not (FALSE, default).

check.duplicates

a logical indicating if duplicate coordinates should be detected; this can be an issue for some graphs; TRUE by default.

Details

There are 7 kinds of graphs proposed:
Delaunay triangulation (type 1)
Gabriel graph (type 2)
Relative neighbours (type 3)
Minimum spanning tree (type 4)
Neighbourhood by distance (type 5)
K nearests neighbours (type 6)
Inverse distances (type 7)

The last option (type=7) is not a true neighbouring graph: all sites are neighbours, but the spatial weights are directly proportional to the inversed spatial distances.
Also not that in this case, the output of the function is always a listw object, even if nb was requested.

The choice of the connection network has been discuted on the adegenet forum. Please search the archives from adegenet website (section 'contact') using 'graph' as keyword.

Value

Returns a connection network having the class nb or listw. The xy coordinates are passed as attribute to the created object.

Author(s)

Thibaut Jombart [email protected]

See Also

spca

Examples

## Not run: 
data(nancycats)

par(mfrow=c(2,2))
cn1 <- chooseCN(nancycats@other$xy,ask=FALSE,type=1)
cn2 <- chooseCN(nancycats@other$xy,ask=FALSE,type=2)
cn3 <- chooseCN(nancycats@other$xy,ask=FALSE,type=3)
cn4 <- chooseCN(nancycats@other$xy,ask=FALSE,type=4)
par(mfrow=c(1,1))

## End(Not run)

Represents a cloud of points with colors

Description

The colorplot function represents a cloud of points with colors corresponding to a combination of 1,2 or 3 quantitative variables, assigned to RGB (Red, Green, Blue) channels. For instance, this can be useful to represent up to 3 principal components in space. Note that the property of such representation to convey multidimensional information has not been investigated.

colorplot is a S3 generic function. Methods are defined for particular objects, like spca objects.

Usage

colorplot(...)

## Default S3 method:
colorplot(xy, X, axes=NULL, add.plot=FALSE, defaultLevel=0, transp=FALSE, alpha=.5, ...)

Arguments

xy

a numeric matrix with two columns (e.g. a matrix of spatial coordinates.

X

a matrix-like containing numeric values that are translated into the RGB system. Variables are considered to be in columns.

axes

the index of the columns of X to be represented. Up to three axes can be chosen. If null, up to the first three columns of X are used.

add.plot

a logical stating whether the colorplot should be added to the existing plot (defaults to FALSE).

defaultLevel

a numeric value between 0 and 1, giving the default level in a color for which values are not specified. Used whenever less than three axes are specified.

transp

a logical stating whether the produced colors should be transparent (TRUE) or not (FALSE, default).

alpha

the alpha level for transparency, between 0 (fully transparent) and 1 (not transparent); see ?rgb for more details.

...

further arguments to be passed to other methods. In colorplot.default, these arguments are passed to plot/points functions. See ?plot.default and ?points.

Value

Invisibly returns a vector of colours used in the plot.

Author(s)

Thibaut Jombart [email protected]

Examples

# a toy example
xy <- expand.grid(1:10,1:10)
df <- data.frame(x=1:100, y=100:1, z=runif(100,0,100))
colorplot(xy,df,cex=10,main="colorplot: toy example")

## Not run: 
# a genetic example using a sPCA
if(require(spdep)){
data(spcaIllus)
dat3 <- spcaIllus$dat3
spca3 <- spca(dat3,xy=dat3$other$xy,ask=FALSE,type=1,plot=FALSE,scannf=FALSE,nfposi=1,nfnega=1)
colorplot(spca3, cex=4, main="colorplot: a sPCA example")
text(spca3$xy[,1], spca3$xy[,2], dat3$pop)
mtext("P1-P2 in cline\tP3 random \tP4 local repulsion")
}

## End(Not run)

Genotype composition plot

Description

The compoplot uses a barplot to represent the group assignment probability of individuals to several groups. It is a generic with methods for the following objects:

Usage

compoplot(x, ...)

## S3 method for class 'matrix'
compoplot(
  x,
  col.pal = funky,
  border = NA,
  subset = NULL,
  show.lab = FALSE,
  lab = rownames(x),
  legend = TRUE,
  txt.leg = colnames(x),
  n.col = 4,
  posi = NULL,
  cleg = 0.8,
  bg = transp("white"),
  ...
)

## S3 method for class 'dapc'
compoplot(x, only.grp = NULL, border = NA, ...)

## S3 method for class 'snapclust'
compoplot(x, border = NA, ...)

Arguments

x

an object to be used for plotting (see description)

...

further arguments to be passed to barplot

col.pal

a color palette to be used for the groups; defaults to funky

border

a color for the border of the barplot; use NA to indicate no border.

subset

a subset of individuals to retain

show.lab

a logical indicating if individual labels should be displayed

lab

a vector of individual labels; if NULL, row.names of the matrix are used

legend

a logical indicating whether a legend should be provided for the colors

txt.leg

a character vector to be used for the legend

n.col

the number of columns to be used for the legend

posi

the position of the legend

cleg

a size factor for the legend

bg

the background to be used for the legend

only.grp

a subset of groups to retain

Details

  • matrix: a matrix with individuals in row and genetic clusters in column, each entry being an assignment probability of the corresponding individual to the corresponding group

  • dapc: the output of the dapc function; in this case, group assignments are based upon geometric criteria in the discriminant space

  • snapclust: the output of the snapclust function; in this case, group assignments are based upon the likelihood of genotypes belonging to their groups

Author(s)

Thibaut Jombart [email protected]


Returns original points in results paths of an object of class 'monmonier'

Description

The original implementation of monmonier in package adegenet returns path coordinates, coords.monmonier additionally displays identities of the original points of the network, based on original coordinates.

Usage

coords.monmonier(x)

Arguments

x

an object of class monmonier.

Value

Returns a list with elements according to the x$nrun result of the monmonier object. Corresponding path points are in the same order as in the original object.

run1 (run2, ...): for each run, a list containing a matrix giving the original points in the network (first and second, indicating pairs of neighbours). Path coordinates are stored in columns x.hw and y.hw. first and second are integers referring to the row numbers in the x$xy matrix of the original monmonier object.

Author(s)

Peter Solymos, [email protected]

See Also

monmonier

Examples

## Not run: 
if(require(spdep)){

load(system.file("files/mondata1.rda",package="adegenet"))
cn1 <- chooseCN(mondata1$xy,type=2,ask=FALSE)
mon1 <- monmonier(mondata1$xy,dist(mondata1$x1),cn1,threshold=2,nrun=3)

mon1$run1
mon1$run2
mon1$run3
path.coords <- coords.monmonier(mon1)
path.coords
}

## End(Not run)

Discriminant Analysis of Principal Components (DAPC)

Description

These functions implement the Discriminant Analysis of Principal Components (DAPC, Jombart et al. 2010). This method descibes the diversity between pre-defined groups. When groups are unknown, use find.clusters to infer genetic clusters. See 'details' section for a succint description of the method, and vignette("adegenet-dapc") for a tutorial. Graphical methods for DAPC are documented in scatter.dapc (see ?scatter.dapc).

dapc is a generic function performing the DAPC on the following types of objects:
- data.frame (only numeric data)
- matrix (only numeric data)
- genind objects (genetic markers)
- genlight objects (genome-wide SNPs)

These methods all return an object with class dapc.

Functions that can be applied to these objects are (the ".dapc" can be ommitted):

- print.dapc: prints the content of a dapc object.
- summary.dapc: extracts useful information from a dapc object.
- predict.dapc: predicts group memberships based on DAPC results.
- xvalDapc: performs cross-validation of DAPC using varying numbers of PCs (and keeping the number of discriminant functions fixed); it currently has methods for data.frame and matrix.

DAPC implementation calls upon dudi.pca from the ade4 package (except for genlight objects) and lda from the MASS package. The predict procedure uses predict.lda from the MASS package.

as.lda is a generic with a method for dapc object which converts these objects into outputs similar to that of lda.default.

Usage

## S3 method for class 'data.frame'
dapc(x, grp, n.pca=NULL, n.da=NULL, center=TRUE,
     scale=FALSE, var.contrib=TRUE, var.loadings=FALSE, pca.info=TRUE,
     pca.select=c("nbEig","percVar"), perc.pca=NULL, ..., dudi=NULL)

## S3 method for class 'matrix'
dapc(x, ...)

## S3 method for class 'genind'
dapc(x, pop=NULL, n.pca=NULL, n.da=NULL, scale=FALSE,
     truenames=TRUE, var.contrib=TRUE, var.loadings=FALSE, pca.info=TRUE,
     pca.select=c("nbEig","percVar"), perc.pca=NULL, ...)

## S3 method for class 'genlight'
dapc(x, pop=NULL, n.pca=NULL, n.da=NULL,
   scale=FALSE, var.contrib=TRUE, var.loadings=FALSE, pca.info=TRUE,
   pca.select=c("nbEig", "percVar"), perc.pca=NULL, glPca=NULL, ...)

## S3 method for class 'dudi'
dapc(x, grp, ...)

## S3 method for class 'dapc'
print(x, ...)

## S3 method for class 'dapc'
summary(object, ...)

## S3 method for class 'dapc'
predict(object, newdata, prior = object$prior, dimen,
         method = c("plug-in", "predictive", "debiased"), ...)

Arguments

x

a data.frame, matrix, or genind object. For the data.frame and matrix arguments, only quantitative variables should be provided.

grp, pop

a factor indicating the group membership of individuals; for scatter, an optional grouping of individuals.

n.pca

an integer indicating the number of axes retained in the Principal Component Analysis (PCA) step. If NULL, interactive selection is triggered.

n.da

an integer indicating the number of axes retained in the Discriminant Analysis step. If NULL, interactive selection is triggered.

center

a logical indicating whether variables should be centred to mean 0 (TRUE, default) or not (FALSE). Always TRUE for genind objects.

scale

a logical indicating whether variables should be scaled (TRUE) or not (FALSE, default). Scaling consists in dividing variables by their (estimated) standard deviation to account for trivial differences in variances.

var.contrib

a logical indicating whether the contribution of original variables (alleles, for genind objects) should be provided (TRUE, default) or not (FALSE). Such output can be useful, but can also create huge matrices when there is a lot of variables.

var.loadings

a logical indicating whether the loadings of original variables (alleles, for genind objects) should be provided (TRUE) or not (FALSE, default). Such output can be useful, but can also create huge matrices when there is a lot of variables.

pca.info

a logical indicating whether information about the prior PCA should be stored (TRUE, default) or not (FALSE). This information is required to predict group membership of new individuals using predict, but makes the object slightly bigger.

pca.select

a character indicating the mode of selection of PCA axes, matching either "nbEig" or "percVar". For "nbEig", the user has to specify the number of axes retained (interactively, or via n.pca). For "percVar", the user has to specify the minimum amount of the total variance to be preserved by the retained axes, expressed as a percentage (interactively, or via perc.pca).

perc.pca

a numeric value between 0 and 100 indicating the minimal percentage of the total variance of the data to be expressed by the retained axes of PCA.

...

further arguments to be passed to other functions. For dapc.matrix, arguments are to match those of dapc.data.frame; for dapc.genlight, arguments passed to glPca

glPca

an optional glPca object; if provided, dimension reduction is not performed (saving computational time) but taken directly from this object.

object

a dapc object.

truenames

a logical indicating whether true (i.e., user-specified) labels should be used in object outputs (TRUE, default) or not (FALSE).

dudi

optionally, a multivariate analysis with the class dudi (from the ade4 package). If provided, prior PCA will be ignored, and this object will be used as a prior step for variable orthogonalisation.

newdata

an optional dataset of individuals whose membership is seeked; can be a data.frame, a matrix, a genind or a genlight object, but object class must match the original ('training') data. In particular, variables must be exactly the same as in the original data. For genind objects, see repool to ensure matching of alleles.

prior, dimen, method

see ?predict.lda.

Details

The Discriminant Analysis of Principal Components (DAPC) is designed to investigate the genetic structure of biological populations. This multivariate method consists in a two-steps procedure. First, genetic data are transformed (centred, possibly scaled) and submitted to a Principal Component Analysis (PCA). Second, principal components of PCA are submitted to a Linear Discriminant Analysis (LDA). A trivial matrix operation allows to express discriminant functions as linear combination of alleles, therefore allowing one to compute allele contributions. More details about the computation of DAPC are to be found in the indicated reference.

DAPC does not infer genetic clusters ex nihilo; for this, see the find.clusters function.

Value

=== dapc objects ===
The class dapc is a list with the following components:

call

the matched call.

n.pca

number of PCA axes retained

n.da

number of DA axes retained

var

proportion of variance conserved by PCA principal components

eig

a numeric vector of eigenvalues.

grp

a factor giving prior group assignment

prior

a numeric vector giving prior group probabilities

assign

a factor giving posterior group assignment

tab

matrix of retained principal components of PCA

loadings

principal axes of DAPC, giving coefficients of the linear combination of retained PCA axes.

ind.coord

principal components of DAPC, giving the coordinates of individuals onto principal axes of DAPC; also called the discriminant functions.

grp.coord

coordinates of the groups onto the principal axes of DAPC.

posterior

a data.frame giving posterior membership probabilities for all individuals and all clusters.

var.contr

(optional) a data.frame giving the contributions of original variables (alleles in the case of genetic data) to the principal components of DAPC.

var.load

(optional) a data.frame giving the loadings of original variables (alleles in the case of genetic data) to the principal components of DAPC.

match.prp

a list, where each item is the proportion of individuals correctly matched to their original population in cross-validation.

=== other outputs ===
Other functions have different outputs:
- summary.dapc returns a list with 6 components: n.dim (number of retained DAPC axes), n.pop (number of groups/populations), assign.prop (proportion of overall correct assignment), assign.per.pop (proportion of correct assignment per group), prior.grp.size (prior group sizes), and post.grp.size (posterior group sizes), xval.dapc, xval.genind and xval (all return a list of four lists, each one with as many items as cross-validation runs. The first item is a list of assign components, the secon is a list of posterior components, the thirs is a list of ind.score components and the fourth is a list of match.prp items, i.e. the prortion of the validation set correctly matched to its original population)

Author(s)

Thibaut Jombart [email protected]

References

Jombart T, Devillard S and Balloux F (2010) Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. BMC Genetics11:94. doi:10.1186/1471-2156-11-94

See Also

Examples

## data(dapcIllus), data(eHGDP), and data(H3N2) illustrate the dapc
## see ?dapcIllus, ?eHGDP, ?H3N2
##
## Not run: 
example(dapcIllus)
example(eHGDP)
example(H3N2)

## End(Not run)

## H3N2 EXAMPLE ##
data(H3N2)
pop(H3N2) <- factor(H3N2$other$epid)
dapc1 <- dapc(H3N2, var.contrib=FALSE, scale=FALSE, n.pca=150, n.da=5)

## remove internal segments and ellipses, different pch, add MStree
scatter(dapc1, cell=0, pch=18:23, cstar=0, mstree=TRUE, lwd=2, lty=2)

## label individuals at the periphery
# air = 2 is a measure of how much space each label needs
# pch = NA suppresses plotting of points
scatter(dapc1, label.inds = list(air = 2, pch = NA))

## only ellipse, custom labels
scatter(dapc1, cell=2, pch="", cstar=0, posi.da="top",
        label=paste("year\n",2001:2006), axesel=FALSE, col=terrain.colors(10))


## SHOW COMPOPLOT ON MICROBOV DATA ##
data(microbov)
dapc1 <- dapc(microbov, n.pca=20, n.da=15)
compoplot(dapc1, lab="")




## Not run: 
## EXAMPLE USING GENLIGHT OBJECTS ##
## simulate data
x <- glSim(50,4e3-50, 50, ploidy=2)
x
plot(x)

## perform DAPC
dapc1 <- dapc(x, n.pca=10, n.da=1)
dapc1

## plot results
scatter(dapc1, scree.da=FALSE)

## SNP contributions
loadingplot(dapc1$var.contr)
loadingplot(tail(dapc1$var.contr, 100), main="Loading plot - last 100 SNPs")



## USE "PREDICT" TO PREDICT GROUPS OF NEW INDIVIDUALS ##
## load data
data(sim2pop)

## we make a dataset of:
## 30 individuals from pop A
## 30 individuals from pop B
## 30 hybrids

## separate populations and make F1
temp <- seppop(sim2pop)
temp <- lapply(temp, function(e) hybridize(e,e,n=30)) # force equal popsizes

## make hybrids
hyb <- hybridize(temp[[1]], temp[[2]], n=30)

## repool data - needed to ensure allele matching
newdat <- repool(temp[[1]], temp[[2]], hyb)
pop(newdat) <- rep(c("pop A", "popB", "hyb AB"), c(30,30,30))

## perform the DAPC on the first 2 pop (60 first indiv)
dapc1 <- dapc(newdat[1:60],n.pca=5,n.da=1)

## plot results
scatter(dapc1, scree.da=FALSE)

## make prediction for the 30 hybrids
hyb.pred <- predict(dapc1, newdat[61:90])
hyb.pred

## plot the inferred coordinates (circles are hybrids)
points(hyb.pred$ind.scores, rep(.1, 30))

## look at assignment using assignplot
assignplot(dapc1, new.pred=hyb.pred)
title("30 indiv popA, 30 indiv pop B, 30 hybrids")

## image using compoplot
compoplot(dapc1, new.pred=hyb.pred, ncol=2)
title("30 indiv popA, 30 indiv pop B, 30 hybrids")

## CROSS-VALIDATION ##
data(sim2pop)
xval <- xvalDapc(sim2pop@tab, pop(sim2pop), n.pca.max=100, n.rep=3)
xval
boxplot(xval$success~xval$n.pca, xlab="Number of PCA components",
ylab="Classification succes", main="DAPC - cross-validation")


## End(Not run)

Cross-validation for Discriminant Analysis of Principal Components (DAPC)

Description

The function xvalDapc performs stratified cross-validation of DAPC using varying numbers of PCs (and keeping the number of discriminant functions fixed); xvalDapc is a generic with methods for data.frame and matrix.

Usage

xvalDapc(x, ...)

## Default S3 method:
xvalDapc(x, grp, n.pca.max = 300, n.da = NULL,
              training.set = 0.9, result = c("groupMean", "overall"),
              center = TRUE, scale = FALSE,
              n.pca=NULL, n.rep = 30, xval.plot = TRUE, ...)

## S3 method for class 'data.frame'
xvalDapc(x, grp, n.pca.max = 300, n.da = NULL,
              training.set = 0.9, result = c("groupMean", "overall"),
              center = TRUE, scale = FALSE,
              n.pca=NULL, n.rep = 30, xval.plot = TRUE, ...)

## S3 method for class 'matrix'
xvalDapc(x, grp, n.pca.max = 300, n.da = NULL,
              training.set = 0.9, result = c("groupMean", "overall"),
              center = TRUE, scale = FALSE,
              n.pca=NULL, n.rep = 30, xval.plot = TRUE, ...)

## S3 method for class 'genlight'
xvalDapc(x, ...)

## S3 method for class 'genind'
xvalDapc(x, ...)

Arguments

x

a data.frame or a matrix used as input of DAPC.

grp

a factor indicating the group membership of individuals.

n.pca.max

maximum number of PCA components to retain.

n.da

an integer indicating the number of axes retained in the Discriminant Analysis step. If NULL, n.da defaults to 1 less than the number of groups.

training.set

the proportion of data (individuals) to be used for the training set; defaults to 0.9 if all groups have >= 10 members; otherwise, training.set scales automatically to the largest proportion that still ensures all groups will be present in both training and validation sets.

result

a character string; "groupMean" for group-wise assignment sucess, or "overall" for an overall mean assignment success; see details.

center

a logical indicating whether variables should be centred to mean 0 (TRUE, default) or not (FALSE). Always TRUE for genind objects.

scale

a logical indicating whether variables should be scaled (TRUE) or not (FALSE, default). Scaling consists in dividing variables by their (estimated) standard deviation to account for trivial differences in variances.

n.pca

an integer vector indicating the number of different number of PCA axes to be retained for the cross validation; if NULL, this will be dertermined automatically.

n.rep

the number of replicates to be carried out at each level of PC retention; defaults to 30.

xval.plot

a logical indicating whether a plot of the cross-validation results should be generated.

...

further arguments to be passed to boot. see Details.

Details

The Discriminant Analysis of Principal Components (DAPC) relies on dimension reduction of the data using PCA followed by a linear discriminant analysis. How many PCA axes to retain is often a non-trivial question. Cross validation provides an objective way to decide how many axes to retain: different numbers are tried and the quality of the corresponding DAPC is assessed by cross- validation: DAPC is performed on a training set, typically made of 90% of the observations (comprising 90% of the observations in each subpopulation) , and then used to predict the groups of the 10% of remaining observations. The current method uses the average prediction success per group (result="groupMean"), or the overall prediction success (result="overall"). The number of PCs associated with the lowest Mean Squared Error is then retained in the DAPC.

Parallel Computing

The permutation of the data for cross-validation is performed in part by the functionboot. If you have a modern computer, it is likely that you have multiple cores on your system. R by default utilizes only one of these cores unless you tell it otherwise. For details, please see the documentation of boot. Basically, if you want to use multiple cores, you need two arguments:

  1. parallel - what R parallel system to use (see below)

  2. ncpus - number of cores you want to use

If you are on a unix system (Linux or OSX), you will want to specify parallel = "multicore". If you are on Windows, you will want to specify parallel = "snow".

Value

A list containing seven items, and a plot of the results. The first is a data.frame with two columns, the first giving the number of PCs of PCA retained in the corresponding DAPC, and the second giving the proportion of successful group assignment for each replicate. The second item gives the mean and confidence interval for random chance. The third gives the mean successful assignment at each level of PC retention. The fourth indicates which number of PCs is associated with the highest mean success. The fifth gives the Root Mean Squared Error at each level of PC retention. The sixth indicates which number of PCs is associated with the lowest MSE. The seventh item contains the DAPC carried out with the optimal number of PCs, determined with reference to MSE.

If xval.plot=TRUE a scatterplot of the results of cross-validation will be displayed.

Author(s)

Caitlin Collins [email protected], Thibaut Jombart [email protected], Zhian N. Kamvar [email protected]

References

Jombart T, Devillard S and Balloux F (2010) Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. BMC Genetics11:94. doi:10.1186/1471-2156-11-94

See Also

dapc

Examples

## Not run: 
## CROSS-VALIDATION ##
data(sim2pop)
xval <- xvalDapc(sim2pop@tab, pop(sim2pop), n.pca.max=100, n.rep=3)
xval

## 100 replicates ##

# Serial version (SLOW!)
system.time(xval <- xvalDapc(sim2pop@tab, pop(sim2pop), n.pca.max=100, n.rep=100))

# Parallel version (faster!)
system.time(xval <- xvalDapc(sim2pop@tab, pop(sim2pop), n.pca.max=100, n.rep=100, 
                             parallel = "multicore", ncpus = 2))

## End(Not run)

Graphics for Discriminant Analysis of Principal Components (DAPC)

Description

These functions provide graphic outputs for Discriminant Analysis of Principal Components (DAPC, Jombart et al. 2010). See ?dapc for details about this method. DAPC graphics are detailed in the DAPC tutorial accessible using vignette("adegenet-dapc").

These functions all require an object of class dapc (the ".dapc" can be ommitted when calling the functions):
- scatter.dapc: produces scatterplots of principal components (or 'discriminant functions'), with a screeplot of eigenvalues as inset.
- assignplot: plot showing the probabilities of assignment of individuals to the different clusters.

Usage

## S3 method for class 'dapc'
scatter(x, xax=1, yax=2, grp=x$grp, col=seasun(length(levels(grp))),
      pch=20, bg="white", solid=.7, scree.da=TRUE,
      scree.pca=FALSE, posi.da="bottomright",
      posi.pca="bottomleft", bg.inset="white", ratio.da=.25,
      ratio.pca=.25, inset.da=0.02, inset.pca=0.02,
      inset.solid=.5, onedim.filled=TRUE, mstree=FALSE, lwd=1,
      lty=1, segcol="black", legend=FALSE, posi.leg="topright",
      cleg=1, txt.leg=levels(grp), cstar = 1, cellipse = 1.5,
      axesell = FALSE, label = levels(grp), clabel = 1, xlim =
      NULL, ylim = NULL, grid = FALSE, addaxes = TRUE, origin =
      c(0,0), include.origin = TRUE, sub = "", csub = 1, possub =
      "bottomleft", cgrid = 1, pixmap = NULL, contour = NULL, area
      = NULL, label.inds = NULL, ...)

assignplot(x, only.grp=NULL, subset=NULL, new.pred=NULL, cex.lab=.75,pch=3)

Arguments

x

a dapc object.

xax, yax

integers specifying which principal components of DAPC should be shown in x and y axes.

grp

a factor defining group membership for the individuals. The scatterplot is optimal only for the default group, i.e. the one used in the DAPC analysis.

col

a suitable color to be used for groups. The specified vector should match the number of groups, not the number of individuals.

pch

a numeric indicating the type of point to be used to indicate the prior group of individuals (see points documentation for more details); one value is expected for each group; recycled if necessary.

bg

the color used for the background of the scatterplot.

solid

a value between 0 and 1 indicating the alpha level for the colors of the plot; 0=full transparency, 1=solid colours.

scree.da

a logical indicating whether a screeplot of Discriminant Analysis eigenvalues should be displayed in inset (TRUE) or not (FALSE).

scree.pca

a logical indicating whether a screeplot of Principal Component Analysis eigenvalues should be displayed in inset (TRUE) or not (FALSE); retained axes are displayed in black.

posi.da

the position of the inset of DA eigenvalues; can match any combination of "top/bottom" and "left/right".

posi.pca

the position of the inset of PCA eigenvalues; can match any combination of "top/bottom" and "left/right".

bg.inset

the color to be used as background for the inset plots.

ratio.da

the size of the inset of DA eigenvalues as a proportion of the current plotting region.

ratio.pca

the size of the inset of PCA eigenvalues as a proportion of the current plotting region.

inset.da

a vector with two numeric values (recycled if needed) indicating the inset to be used for the screeplot of DA eigenvalues as a proportion of the current plotting region; see ?add.scatter for more details.

inset.pca

a vector with two numeric values (recycled if needed) indicating the inset to be used for the screeplot of PCA eigenvalues as a proportion of the current plotting region; see ?add.scatter for more details.

inset.solid

a value between 0 and 1 indicating the alpha level for the colors of the inset plots; 0=full transparency, 1=solid colours.

onedim.filled

a logical indicating whether curves should be filled when plotting a single discriminant function (TRUE), or not (FALSE).

mstree

a logical indicating whether a minimum spanning tree linking the groups and based on the squared distances between the groups inside the entire space should added to the plot (TRUE), or not (FALSE).

lwd, lty, segcol

the line width, line type, and segment colour to be used for the minimum spanning tree.

legend

a logical indicating whether a legend for group colours should added to the plot (TRUE), or not (FALSE).

posi.leg

the position of the legend for group colours; can match any combination of "top/bottom" and "left/right", or a set of x/y coordinates stored as a list (locator can be used).

cleg

a size factor used for the legend.

cstar, cellipse, axesell, label, clabel, xlim, ylim, grid, addaxes, origin, include.origin, sub, csub, possub, cgrid, pixmap, contour, area

arguments passed to s.class; see ?s.class for more informations

only.grp

a character vector indicating which groups should be displayed. Values should match values of x$grp. If NULL, all results are displayed

subset

integer or logical vector indicating which individuals should be displayed. If NULL, all results are displayed

new.pred

an optional list, as returned by the predict method for dapc objects; if provided, the individuals with unknown groups are added at the bottom of the plot. To visualize these individuals only, specify only.grp="unknown".

cex.lab

a numeric indicating the size of labels.

txt.leg

a character vector indicating the text to be used in the legend; if not provided, group names stored in x$grp are used.

label.inds

Named list of arguments passed to the orditorp function. This will label individual points witout overlapping. Arguments x and display are hardcoded and should not be specified by user.

...

further arguments to be passed to other functions. For scatter, arguments passed to points; for compoplot, arguments passed to barplot.

Details

See the documentation of dapc for more information about the method.

Value

All functions return the matched call.

Author(s)

Thibaut Jombart [email protected]

References

Jombart T, Devillard S and Balloux F (2010) Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. BMC Genetics11:94. doi:10.1186/1471-2156-11-94

See Also

- dapc: implements the DAPC.

- find.clusters: to identify clusters without prior.

- dapcIllus: a set of simulated data illustrating the DAPC

- eHGDP, H3N2: empirical datasets illustrating DAPC

Examples

## Not run: 
data(H3N2)
dapc1 <- dapc(H3N2, pop=H3N2$other$epid, n.pca=30,n.da=6)

## defautl plot ##
scatter(dapc1)

## label individuals at the periphery
# air = 2 is a measure of how much space each label needs
# pch = NA suppresses plotting of points
scatter(dapc1, label.inds = list(air = 2, pch = NA))

## showing different scatter options ##
## remove internal segments and ellipses, different pch, add MStree
scatter(dapc1, pch=18:23, cstar=0, mstree=TRUE, lwd=2, lty=2, posi.da="topleft")

## only ellipse, custom labels, use insets
scatter(dapc1, cell=2, pch="", cstar=0, posi.pca="topleft", posi.da="topleft", scree.pca=TRUE,
inset.pca=c(.01,.3), label=paste("year\n",2001:2006), axesel=FALSE, col=terrain.colors(10))

## without ellipses, use legend for groups
scatter(dapc1, cell=0, cstar=0, scree.da=FALSE, clab=0, cex=3,
solid=.4, bg="white", leg=TRUE, posi.leg="topleft")

## only one axis
scatter(dapc1,1,1,scree.da=FALSE, legend=TRUE, solid=.4,bg="white")



## example using genlight objects ##
## simulate data
x <- glSim(50,4e3-50, 50, ploidy=2)
x
plot(x)

## perform DAPC
dapc2 <- dapc(x, n.pca=10, n.da=1)
dapc2

## plot results
scatter(dapc2, scree.da=FALSE, leg=TRUE, txt.leg=paste("group",
c('A','B')), col=c("red","blue"))

## SNP contributions
loadingplot(dapc2$var.contr)
loadingplot(tail(dapc2$var.contr, 100), main="Loading plot - last 100 SNPs")



## assignplot / compoplot ##
assignplot(dapc1, only.grp=2006)

data(microbov)
dapc3 <- dapc(microbov, n.pca=20, n.da=15)
compoplot(dapc3, lab="")

## End(Not run)

Simulated data illustrating the DAPC

Description

Datasets illustrating the Discriminant Analysis of Principal Components (DAPC, Jombart et al. submitted).

Format

dapcIllus is list of 4 components being all genind objects.

Details

These data were simulated using various models using Easypop (2.0.1). The dapcIllus is a list containing the following genind objects:
- "a": island model with 6 populations
- "b": hierarchical island model with 6 populations (3,2,1)
- "c": one-dimensional stepping stone with 2x6 populations, and a boundary between the two sets of 6 populations
- "d": one-dimensional stepping stone with 24 populations

See "source" for a reference providing simulation details.

Author(s)

Thibaut Jombart [email protected]

Source

Jombart, T., Devillard, S. and Balloux, F. Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. Submitted to BMC genetics.

References

Jombart, T., Devillard, S. and Balloux, F. Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. Submitted to Genetics.

See Also

- dapc: implements the DAPC.

- eHGDP: dataset illustrating the DAPC and find.clusters.

- H3N2: dataset illustrating the DAPC.

- find.clusters: to identify clusters without prior.

Examples

## Not run: 

data(dapcIllus)
attach(dapcIllus)
a # this is a genind object, like b, c, and d.


## FINS CLUSTERS EX NIHILO
clust.a <- find.clusters(a, n.pca=100, n.clust=6)
clust.b <- find.clusters(b, n.pca=100, n.clust=6)
clust.c <- find.clusters(c, n.pca=100, n.clust=12)
clust.d <- find.clusters(d, n.pca=100, n.clust=24)

## examin outputs
names(clust.a)
lapply(clust.a, head)


## PERFORM DAPCs
dapc.a <- dapc(a, pop=clust.a$grp, n.pca=100, n.da=5)
dapc.b <- dapc(b, pop=clust.b$grp, n.pca=100, n.da=5)
dapc.c <- dapc(c, pop=clust.c$grp, n.pca=100, n.da=11)
dapc.d <- dapc(d, pop=clust.d$grp, n.pca=100, n.da=23)


## LOOK AT ONE RESULT
dapc.a
summary(dapc.a)

## FORM A LIST OF RESULTS FOR THE 4 DATASETS
lres <- list(dapc.a, dapc.b, dapc.c, dapc.d)


## DRAW 4 SCATTERPLOTS
par(mfrow=c(2,2))
lapply(lres, scatter)


# detach data
detach(dapcIllus)

## End(Not run)

Convert a data.frame of allele data to a genind object.

Description

The function df2genind converts a data.frame (or a matrix) into a genind object. The data.frame must meet the following requirements:

  • genotypes are in row (one row per genotype)

  • markers/loci are in columns

  • each element is a string of characters coding alleles, ideally separated by a character string (argument sep); if no separator is used, the number of characters coding alleles must be indicated (argument ncode).

Usage

df2genind(
  X,
  sep = NULL,
  ncode = NULL,
  ind.names = NULL,
  loc.names = NULL,
  pop = NULL,
  NA.char = "",
  ploidy = 2,
  type = c("codom", "PA"),
  strata = NULL,
  hierarchy = NULL,
  check.ploidy = getOption("adegenet.check.ploidy")
)

Arguments

X

a matrix or a data.frame containing allelle data only (see decription)

sep

a character string separating alleles. See details.

ncode

an optional integer giving the number of characters used for coding one genotype at one locus. If not provided, this is determined from data.

ind.names

optinal, a vector giving the individuals names; if NULL, taken from rownames of X. If factor or numeric, vector is converted to character.

loc.names

an optional character vector giving the markers names; if NULL, taken from colnames of X.

pop

an optional factor giving the population of each individual.

NA.char

a character string corresponding to missing allele (to be treated as NA)

ploidy

an integer indicating the degree of ploidy of the genotypes.

type

a character string indicating the type of marker: 'codom' stands for 'codominant' (e.g. microstallites, allozymes); 'PA' stands for 'presence/absence' markers (e.g. AFLP, RAPD).

strata

an optional data frame that defines population stratifications for your samples. This is especially useful if you have a hierarchical or factorial sampling design.

hierarchy

a hierarchical formula that explicitely defines hierarchical levels in your strata. see hierarchy for details.

check.ploidy

a boolean indicating if the ploidy should be checked (TRUE, default) or not (FALSE). Not checking the ploidy makes the import much faster, but might result in bugs/problems if the input file is misread or the ploidy is wrong. It is therefore advised to first import and check a subset of data to see if everything works as expected before setting this option to false.

Details

See genind2df to convert genind objects back to such a data.frame.

=== Details for the sep argument ===
this character is directly used in reguar expressions like gsub, and thus require some characters to be preceeded by double backslashes. For instance, "/" works but "|" must be coded as "\|".

Value

an object of the class genind for df2genind; a matrix of biallelic genotypes for genind2df

Author(s)

Thibaut Jombart [email protected], Zhian N. Kamvar [email protected]

See Also

genind2df, import2genind, read.genetix, read.fstat, read.structure

Examples

## simple example
df <- data.frame(locusA=c("11","11","12","32"),
locusB=c(NA,"34","55","15"),locusC=c("22","22","21","22"))
row.names(df) <- .genlab("genotype",4)
df

obj <- df2genind(df, ploidy=2, ncode=1)
obj
tab(obj)


## converting a genind as data.frame
genind2df(obj)
genind2df(obj, sep="/")

Genetic distances between populations

Description

This function computes measures of genetic distances between populations using a genpop object.
Currently, five distances are available, some of which are euclidian (see details).

A non-euclidian distance can be transformed into an Euclidean one using cailliez in order to perform a Principal Coordinate Analysis dudi.pco (both functions in ade4).

The function dist.genpop is based on former dist.genet function of ade4 package.

Usage

dist.genpop(x, method = 1, diag = FALSE, upper = FALSE)

Arguments

x

a list of class genpop

method

an integer between 1 and 5. See details

diag

a logical value indicating whether the diagonal of the distance matrix should be printed by print.dist

upper

a logical value indicating whether the upper triangle of the distance matrix should be printed by print.dist

Details

Let A a table containing allelic frequencies with t populations (rows) and m alleles (columns).
Let ν\nu the number of loci. The locus j gets m(j) alleles. m=j=1νm(j)m=\sum_{j=1}^{\nu} m(j)

For the row i and the modality k of the variable j, notice the value aijka_{ij}^k (1it1 \leq i \leq t, 1jν1 \leq j \leq \nu, 1km(j)1 \leq k \leq m(j)) the value of the initial table.

aij+=k=1m(j)aijka_{ij}^+=\sum_{k=1}^{m(j)}a_{ij}^k and pijk=aijkaij+p_{ij}^k=\frac{a_{ij}^k}{a_{ij}^+}

Let P the table of general term pijkp_{ij}^k
pij+=k=1m(j)pijk=1p_{ij}^+=\sum_{k=1}^{m(j)}p_{ij}^k=1, pi++=j=1νpij+=νp_{i+}^+=\sum_{j=1}^{\nu}p_{ij}^+=\nu, p+++=j=1νpi++=tνp_{++}^+=\sum_{j=1}^{\nu}p_{i+}^+=t\nu

The option method computes the distance matrices between populations using the frequencies pijkp_{ij}^k.

1. Nei's distance (not Euclidean):
D1(a,b)=ln(k=1νj=1m(k)pajkpbjkk=1νj=1m(k)(pajk)2k=1νj=1m(k)(pbjk)2)D_1(a,b)=- \ln(\frac{\sum_{k=1}^{\nu} \sum_{j=1}^{m(k)} p_{aj}^k p_{bj}^k}{\sqrt{\sum_{k=1}^{\nu} \sum_{j=1}^{m(k)} {(p_{aj}^k) }^2}\sqrt{\sum_{k=1}^{\nu} \sum_{j=1}^{m(k)} {(p_{bj}^k)}^2}})

2. Angular distance or Edwards' distance (Euclidean):
D2(a,b)=11νk=1νj=1m(k)pajkpbjkD_2(a,b)=\sqrt{1-\frac{1}{\nu} \sum_{k=1}^{\nu} \sum_{j=1}^{m(k)} \sqrt{p_{aj}^k p_{bj}^k}}

3. Coancestrality coefficient or Reynolds' distance (Eucledian):
D3(a,b)=k=1νj=1m(k)(pajkpbjk)22k=1ν(1j=1m(k)pajkpbjk)D_3(a,b)=\sqrt{\frac{\sum_{k=1}^{\nu} \sum_{j=1}^{m(k)}{(p_{aj}^k - p_{bj}^k)}^2}{2 \sum_{k=1}^{\nu} (1- \sum_{j=1}^{m(k)}p_{aj}^k p_{bj}^k)}}

4. Classical Euclidean distance or Rogers' distance (Eucledian):
D4(a,b)=1νk=1ν12j=1m(k)(pajkpbjk)2D_4(a,b)=\frac{1}{\nu} \sum_{k=1}^{\nu} \sqrt{\frac{1}{2} \sum_{j=1}^{m(k)}{(p_{aj}^k - p_{bj}^k)}^2}

5. Absolute genetics distance or Provesti 's distance (not Euclidean):
D5(a,b)=12νk=1νj=1m(k)pajkpbjkD_5(a,b)=\frac{1}{2{\nu}} \sum_{k=1}^{\nu} \sum_{j=1}^{m(k)} |p_{aj}^k - p_{bj}^k|

Value

returns a distance matrix of class dist between the rows of the data frame

Author(s)

Thibaut Jombart [email protected]
Former dist.genet code by Daniel Chessel [email protected]
and documentation by Anne B. Dufour [email protected]

References

To complete informations about distances:

Distance 1:
Nei, M. (1972) Genetic distances between populations. American Naturalist, 106, 283–292.
Nei M. (1978) Estimation of average heterozygosity and genetic distance from a small number of individuals. Genetics, 23, 341–369.
Avise, J. C. (1994) Molecular markers, natural history and evolution. Chapman & Hall, London.

Distance 2:
Edwards, A.W.F. (1971) Distance between populations on the basis of gene frequencies. Biometrics, 27, 873–881.
Cavalli-Sforza L.L. and Edwards A.W.F. (1967) Phylogenetic analysis: models and estimation procedures. Evolution, 32, 550–570.
Hartl, D.L. and Clark, A.G. (1989) Principles of population genetics. Sinauer Associates, Sunderland, Massachussetts (p. 303).

Distance 3:
Reynolds, J. B., B. S. Weir, and C. C. Cockerham. (1983) Estimation of the coancestry coefficient: basis for a short-term genetic distance. Genetics, 105, 767–779.

Distance 4:
Rogers, J.S. (1972) Measures of genetic similarity and genetic distances. Studies in Genetics, Univ. Texas Publ., 7213, 145–153.
Avise, J. C. (1994) Molecular markers, natural history and evolution. Chapman & Hall, London.

Distance 5:
Prevosti A. (1974) La distancia genetica entre poblaciones. Miscellanea Alcobe, 68, 109–118.
Prevosti A., Ocaña J. and Alonso G. (1975) Distances between populations of Drosophila subobscura, based on chromosome arrangements frequencies. Theoretical and Applied Genetics, 45, 231–241.

For more information on dissimilarity indexes:
Gower J. and Legendre P. (1986) Metric and Euclidean properties of dissimilarity coefficients. Journal of Classification, 3, 5–48

Legendre P. and Legendre L. (1998) Numerical Ecology, Elsevier Science B.V. 20, pp274–288.

See Also

cailliez,dudi.pco

Examples

## Not run: 
data(microsatt)
obj <- as.genpop(microsatt$tab)

listDist <- lapply(1:5, function(i) cailliez(dist.genpop(obj,met=i)))
for(i in 1:5) {attr(listDist[[i]],"Labels") <- popNames(obj)}
listPco <- lapply(listDist, dudi.pco,scannf=FALSE)

par(mfrow=c(2,3))
for(i in 1:5) {scatter(listPco[[i]],sub=paste("Dist:", i))}


## End(Not run)

Extended HGDP-CEPH dataset

Description

This dataset consists of 1350 individuals from native Human populations distributed worldwide typed at 678 microsatellite loci. The original HGDP-CEPH panel [1-3] has been extended by several native American populations [4]. This dataset was used to illustrate the Discriminant Analysis of Principal Components (DAPC, [5]).

Format

eHGDP is a genind object with a data frame named popInfo as supplementary component (eHGDP@other$popInfo), which contains the following variables:

Population:

a character vector indicating populations.

Region:

a character vector indicating the geographic region of each population.

Label:

a character vector indicating the correspondence with population labels used in the genind object (i.e., as output by pop(eHGDP)).

Latitude,Longitude:

geographic coordinates of the populations, indicated as north and east degrees.

Source

Original panel by Human Genome Diversity Project (HGDP) and Centre d'Etude du Polymorphisme Humain (CEPH). See reference [4] for Native American populations.

This copy of the dataset was prepared by Francois Balloux.

References

[1] Rosenberg NA, Pritchard JK, Weber JL, Cann HM, Kidd KK, et al. (2002) Genetic structure of human populations. Science 298: 2381-2385.

[2] Ramachandran S, Deshpande O, Roseman CC, Rosenberg NA, Feldman MW, et al. (2005) Support from the relationship of genetic and geographic distance in human populations for a serial founder effect originating in Africa. Proc Natl Acad Sci U S A 102: 15942-15947.

[3] Cann HM, de Toma C, Cazes L, Legrand MF, Morel V, et al. (2002) A human genome diversity cell line panel. Science 296: 261-262.

[4] Wang S, Lewis CM, Jakobsson M, Ramachandran S, Ray N, et al. (2007) Genetic Variation and Population Structure in Native Americans. PLoS Genetics 3: e185.

[5] Jombart, T., Devillard, S. and Balloux, F. Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. Submitted to BMC genetics.

Examples

## Not run: 
## LOAD DATA
data(eHGDP)
eHGDP


## PERFORM DAPC - USE POPULATIONS AS CLUSTERS
## to reproduce exactly analyses from the paper, use "n.pca=1000"
dapc1 <- dapc(eHGDP, all.contrib=TRUE, scale=FALSE,
n.pca=200, n.da=80) # takes 2 minutes
dapc1

## (see ?dapc for details about the output)



## SCREEPLOT OF EIGENVALUES
barplot(dapc1$eig, main="eHGDP - DAPC eigenvalues",
col=c("red","green","blue", rep("grey", 1000)))



## SCATTERPLOTS
## (!) Note: colors may be inverted with respect to [5]
## as signs of principal components are arbitrary
## and change from one computer to another
##
## axes 1-2
s.label(dapc1$grp.coord[,1:2], clab=0, sub="Axes 1-2")
par(xpd=T)
colorplot(dapc1$grp.coord[,1:2], dapc1$grp.coord, cex=3, add=TRUE)
add.scatter.eig(dapc1$eig,10,1,2, posi="bottomright", ratio=.3, csub=1.25)

## axes 2-3
s.label(dapc1$grp.coord[,2:3], clab=0, sub="Axes 2-3")
par(xpd=T)
colorplot(dapc1$grp.coord[,2:3], dapc1$grp.coord, cex=3, add=TRUE)
add.scatter.eig(dapc1$eig,10,1,2, posi="bottomright", ratio=.3, csub=1.25)



## MAP DAPC1 RESULTS
if(require(maps)){

xy <- cbind(eHGDP$other$popInfo$Longitude, eHGDP$other$popInfo$Latitude)

par(mar=rep(.1,4))
map(fill=TRUE, col="lightgrey")
colorplot(xy, -dapc1$grp.coord, cex=3, add=TRUE, trans=FALSE)
}



## LOOK FOR OTHER CLUSTERS
## to reproduce results of the reference paper, use :
## grp <- find.clusters(eHGDP, max.n=50, n.pca=200, scale=FALSE)
## and then
## plot(grp$Kstat, type="b", col="blue")

grp <- find.clusters(eHGDP, max.n=30, n.pca=200,
scale=FALSE, n.clust=4) # takes about 2 minutes
names(grp)

## (see ?find.clusters for details about the output)



## PERFORM DAPC - USE POPULATIONS AS CLUSTERS
## to reproduce exactly analyses from the paper, use "n.pca=1000"
dapc2 <- dapc(eHGDP, pop=grp$grp, all.contrib=TRUE,
scale=FALSE, n.pca=200, n.da=80) # takes around a 1 minute
dapc2


## PRODUCE SCATTERPLOT
scatter(dapc2) # axes 1-2
scatter(dapc2,2,3) # axes 2-3


## MAP DAPC2 RESULTS
if(require(maps)){
xy <- cbind(eHGDP$other$popInfo$Longitude,
eHGDP$other$popInfo$Latitude)

myCoords <- apply(dapc2$ind.coord, 2, tapply, pop(eHGDP), mean)

par(mar=rep(.1,4))
map(fill=TRUE, col="lightgrey")
colorplot(xy, myCoords, cex=3, add=TRUE, trans=FALSE)
}


## End(Not run)

Export analysis for mvmapper visualisation

Description

mvmapper is an interactive tool for visualising outputs of a multivariate analysis on a map from a web browser. The function export_to_mvmapper is a generic with methods for several standard classes of analyses in adegenet and ade4. Information on individual locations, as well as any other relevant data, is passed through the second argument info. By default, the function returns a formatted data.frame and writes the output to a .csv file.

Usage

export_to_mvmapper(x, ...)

## Default S3 method:
export_to_mvmapper(x, ...)

## S3 method for class 'dapc'
export_to_mvmapper(x, info, write_file = TRUE, out_file = NULL, ...)

## S3 method for class 'dudi'
export_to_mvmapper(x, info, write_file = TRUE, out_file = NULL, ...)

## S3 method for class 'spca'
export_to_mvmapper(x, info, write_file = TRUE, out_file = NULL, ...)

Arguments

x

The analysis to be exported. Can be a dapc, spca, or a dudi object.

...

Further arguments to pass to other methods.

info

A data.frame with additional information containing at least the following columns: key (unique individual identifier), lat (latitude), and lon (longitude). Other columns will be exported as well, but are optional.

write_file

A logical indicating if the output should be written out to a .csv file. Defaults to TRUE.

out_file

A character string indicating the file to which the output should be written. If NULL, the file used will be named 'mvmapper_data_[date and time].csv'

Details

mvmapper can be found at: https://popphylotools.github.io/mvMapper/

Value

A data.frame which can serve as input to mvmapper, containing at least the following columns:

  • key: unique individual identifiers

  • PC1: first principal component; further principal components are optional, but if provided will be numbered and follow PC1.

  • lat: latitude for each individual

  • lon: longitude for each individual

In addition, specific information is added for some analyses:

  • spca: Lag_PC columns contain the lag-vectors of the principal components; the lag operator computes, for each individual, the average score of neighbouring individuals; it is useful for clarifying patches and clines.

  • dapc: grp is the group used in the analysis; assigned_grp is the group assignment based on the discriminant functions; support is the statistical support (i.e. assignment probability) for assigned_grp.

Author(s)

Thibaut Jombart [email protected]

See Also

mvmapper is available at: https://popphylotools.github.io/mvMapper/

Examples

# An example using the microsatellite dataset of Dupuis et al. 2016 (781
# individuals, 10 loci, doi: 10.1111/jeb.12931)

# Reading input file from adegenet

input_data <- system.file("data/swallowtails.rda", package="adegenet")
data(swallowtails)


# conducting a DAPC (n.pca determined using xvalDapc, see ??xvalDapc)

dapc1 <- dapc(swallowtails, n.pca=40, n.da=200)


# read in swallowtails_loc.csv, which contains "key", "lat", and "lon"
# columns with column headers (this example contains additional columns
# containing species identifications, locality descriptions, and COI
# haplotype clades)

input_locs <- system.file("files/swallowtails_loc.csv", package = "adegenet")
loc <- read.csv(input_locs, header = TRUE)


# generate mvmapper input file, automatically write the output to a csv, and
# name the output csv "mvMapper_Data.csv"
out_dir <- tempdir()
out_file <- file.path(out_dir, "mvMapper_Data.csv")

out <- export_to_mvmapper(dapc1, loc, write_file = TRUE, out_file = out_file)

Read large DNA alignments into R

Description

The function fasta2DNAbin reads alignments with the fasta format (extensions ".fasta", ".fas", or ".fa"), and outputs a DNAbin object (the efficient DNA representation from the ape package). The output contains either the full alignments, or only SNPs. This implementation is designed for memory-efficiency, and can read in larger datasets than Ape's read.dna.

The function reads data by chunks of a few genomes (minimum 1, no maximum) at a time, which allows one to read massive datasets with negligible RAM requirements (albeit at a cost of computational time). The argument chunkSize indicates the number of genomes read at a time. Increasing this value decreases the computational time required to read data in, while increasing memory requirements.

Usage

fasta2DNAbin(file, quiet=FALSE, chunkSize=10, snpOnly=FALSE)

Arguments

file

a character string giving the path to the file to convert, with the extension ".fa", ".fas", or ".fasta".

Can also be a connection (which will be opened for reading if necessary, and if so closed (and hence destroyed) at the end of the function call).

quiet

a logical stating whether a conversion messages should be printed (FALSE, default) or not (TRUE).

chunkSize

an integer indicating the number of genomes to be read at a time; larger values require more RAM but decrease the time needed to read the data.

snpOnly

a logical indicating whether SNPs only should be returned.

Value

an object of the class DNAbin

Author(s)

Thibaut Jombart [email protected]

See Also

- ?DNAbin for a description of the class DNAbin.

- read.snp: read SNPs in adegenet's '.snp' format.

- read.PLINK: read SNPs in PLINK's '.raw' format.

- df2genind: convert any multiallelic markers into adegenet genind.

- import2genind: read multiallelic markers from various software into adegenet.

Examples

## Not run: 
## show the example file ##
## this is the path to the file:
myPath <- system.file("files/usflu.fasta",package="adegenet")
myPath

## read the file
obj <- fasta2DNAbin(myPath, chunk=10) # process 10 sequences at a time
obj

## End(Not run)

Extract Single Nucleotide Polymorphism (SNPs) from alignments

Description

The function fasta2genlight reads alignments with the fasta format (extensions ".fasta", ".fas", or ".fa"), extracts the binary SNPs, and converts the output into a genlight object.

The function reads data by chunks of a few genomes (minimum 1, no maximum) at a time, which allows one to read massive datasets with negligible RAM requirements (albeit at a cost of computational time). The argument chunkSize indicates the number of genomes read at a time. Increasing this value decreases the computational time required to read data in, while increasing memory requirements.

Multiple cores can be used to decrease the overall computational time on parallel architectures (needs the package parallel).

Usage

fasta2genlight(file, quiet = FALSE, chunkSize = 1000, saveNbAlleles = FALSE,
               parallel = FALSE, n.cores = NULL, ...)

Arguments

file

a character string giving the path to the file to convert, with the extension ".fa", ".fas", or ".fasta".

quiet

logical stating whether a conversion messages should be printed (FALSE,default) or not (TRUE).

chunkSize

an integer indicating the number of genomes to be read at a time; larger values require more RAM but decrease the time needed to read the data.

saveNbAlleles

a logical indicating whether the number of alleles for each loci in the original alignment should be saved in the other slot (TRUE), or not (FALSE, default). In large genomes, this takes some space but allows for tracking SNPs with more than 2 alleles, lost during the conversion.

parallel

a logical indicating whether multiple cores -if available- should be used for the computations (TRUE, default), or not (FALSE); requires the package parallel to be installed (see details).

n.cores

if parallel is TRUE, the number of cores to be used in the computations; if NULL, then the maximum number of cores available on the computer is used.

...

other arguments to be passed to other functions - currently not used.

Details

=== Using multiple cores ===

Most recent machines have one or several processors with multiple cores. R processes usually use one single core. The package parallel allows for parallelizing some computations on multiple cores, which decreases drastically computational time.

To use this functionality, you need to have the last version of the parallel package installed.

Value

an object of the class genlight

Author(s)

Thibaut Jombart [email protected]

See Also

- ?genlight for a description of the class genlight.

- read.snp: read SNPs in adegenet's '.snp' format.

- read.PLINK: read SNPs in PLINK's '.raw' format.

- df2genind: convert any multiallelic markers into adegenet genind.

- import2genind: read multiallelic markers from various software into adegenet.

Examples

## Not run: 
## show the example file ##
## this is the path to the file:
myPath <- system.file("files/usflu.fasta",package="adegenet")
myPath

## read the file
obj <- fasta2genlight(myPath, chunk=10) # process 10 sequences at a time
obj

## look at extracted information
position(obj)
alleles(obj)
locNames(obj)

## plot positions of polymorphic sites
temp <- density(position(obj), bw=10)
plot(temp, xlab="Position in the alignment", lwd=2, main="Location of the SNPs")
points(position(obj), rep(0, nLoc(obj)), pch="|", col="red")

## End(Not run)

find.cluster: cluster identification using successive K-means

Description

These functions implement the clustering procedure used in Discriminant Analysis of Principal Components (DAPC, Jombart et al. 2010). This procedure consists in running successive K-means with an increasing number of clusters (k), after transforming data using a principal component analysis (PCA). For each model, a statistical measure of goodness of fit (by default, BIC) is computed, which allows to choose the optimal k. See details for a description of how to select the optimal k and vignette("adegenet-dapc") for a tutorial.

Optionally, hierarchical clustering can be sought by providing a prior clustering of individuals (argument clust). In such case, clusters will be sought within each prior group.

The K-means procedure used in find.clusters is kmeans function from the stats package. The PCA function is dudi.pca from the ade4 package, except for genlight objects which use the glPca procedure from adegenet.

find.clusters is a generic function with methods for the following types of objects:

  • data.frame (only numeric data)

  • matrix (only numeric data)

  • genind objects (genetic markers)

  • genlight objects (genome-wide SNPs)

Usage

## S3 method for class 'data.frame'
find.clusters(x, clust = NULL, n.pca = NULL, n.clust =
              NULL, method = c("kmeans", "ward"), stat = c("BIC","AIC", "WSS"),
              choose.n.clust = TRUE, criterion = c("diffNgroup", "min","goesup",
              "smoothNgoesup", "goodfit"), max.n.clust = round(nrow(x)/10),
              n.iter = 1e5, n.start = 10, center = TRUE, scale = TRUE,
              pca.select = c("nbEig","percVar"), perc.pca = NULL, ..., dudi =
              NULL)

## S3 method for class 'matrix'
find.clusters(x, ...)

## S3 method for class 'genind'
find.clusters(x, clust = NULL, n.pca = NULL, n.clust = NULL,
              method = c("kmeans", "ward"), stat = c("BIC","AIC", "WSS"),
              choose.n.clust = TRUE, criterion = c("diffNgroup", "min","goesup",
              "smoothNgoesup", "goodfit"), max.n.clust = round(nrow(x@tab)/10),
              n.iter = 1e5, n.start = 10, scale = FALSE, truenames = TRUE,
              ...)

## S3 method for class 'genlight'
find.clusters(x, clust = NULL, n.pca = NULL, n.clust = NULL,
              method = c("kmeans", "ward"), stat = c("BIC", "AIC", "WSS"),
              choose.n.clust = TRUE, criterion = c("diffNgroup",
              "min","goesup","smoothNgoesup", "goodfit"), max.n.clust =
              round(nInd(x)/10), n.iter = 1e5,n.start = 10, scale = FALSE,
              pca.select = c("nbEig","percVar"), perc.pca = NULL,glPca=NULL,
              ...)

Arguments

x

a data.frame, matrix, or genind object. For the data.frame and matrix arguments, only quantitative variables should be provided.

clust

an optional factor indicating a prior group membership of individuals. If provided, sub-clusters will be sought within each prior group.

n.pca

an integer indicating the number of axes retained in the Principal Component Analysis (PCA) step. If NULL, interactive selection is triggered.

n.clust

an optinal integer indicating the number of clusters to be sought. If provided, the function will only run K-means once, for this number of clusters. If left as NULL, several K-means are run for a range of k (number of clusters) values.

method

a character string indicating the type of clustering method to be used; "kmeans" (default) uses K-means clustering, and is the original implementation of find.clusters; "ward" is an alternative which uses Ward's hierarchical clustering; this latter method seems to be more reliable on some simulated datasets, but will be less computer-efficient for large numbers (thousands) of individuals.

stat

a character string matching 'BIC', 'AIC', or 'WSS', which indicates the statistic to be computed for each model (i.e., for each value of k). BIC: Bayesian Information Criterion. AIC: Aikaike's Information Criterion. WSS: within-groups sum of squares, that is, residual variance.

choose.n.clust

a logical indicating whether the number of clusters should be chosen by the user (TRUE, default), or automatically, based on a given criterion (argument criterion). It is HIGHLY RECOMMENDED to choose the number of clusters INTERACTIVELY, since i) the decrease of the summary statistics (BIC by default) is informative, and ii) no criteria for automatic selection is appropriate to all cases (see details).

criterion

a character string matching "diffNgroup", "min","goesup", "smoothNgoesup", or "goodfit", indicating the criterion for automatic selection of the optimal number of clusters. See details for an explanation of these procedures.

max.n.clust

an integer indicating the maximum number of clusters to be tried. Values of 'k' will be picked up between 1 and max.n.clust

n.iter

an integer indicating the number of iterations to be used in each run of K-means algorithm. Corresponds to iter.max of kmeans function.

n.start

an integer indicating the number of randomly chosen starting centroids to be used in each run of the K-means algorithm. Using more starting points ensures convergence of the algorithm. Corresponds to nstart of kmeans function.

center

a logical indicating whether variables should be centred to mean 0 (TRUE, default) or not (FALSE). Always TRUE for genind objects.

scale

a logical indicating whether variables should be scaled (TRUE) or not (FALSE, default). Scaling consists in dividing variables by their (estimated) standard deviation to account for trivial differences in variances. In allele frequencies, it comes with the risk of giving uninformative alleles more importance while downweighting informative alleles. Further scaling options are available for genind objects (see argument scale.method).

pca.select

a character indicating the mode of selection of PCA axes, matching either "nbEig" or "percVar". For "nbEig", the user has to specify the number of axes retained (interactively, or via n.pca). For "percVar", the user has to specify the minimum amount of the total variance to be preserved by the retained axes, expressed as a percentage (interactively, or via perc.pca).

perc.pca

a numeric value between 0 and 100 indicating the minimal percentage of the total variance of the data to be expressed by the retained axes of PCA.

truenames

a logical indicating whether true (i.e., user-specified) labels should be used in object outputs (TRUE, default) or not (FALSE), in which case generic labels are used.

...

further arguments to be passed to other functions. For find.clusters.matrix, arguments are to match those of the data.frame method.

dudi

optionally, a multivariate analysis with the class dudi (from the ade4 package). If provided, prior PCA will be ignored, and this object will be used as a prior step for variable orthogonalisation.

glPca

an optional glPca object; if provided, dimension reduction is not performed (saving computational time) but taken directly from this object.

Details

=== ON THE SELECTION OF K ===
(where K is the 'optimal' number of clusters)

So far, the analysis of data simulated under various population genetics models (see reference) suggested an ad hoc rule for the selection of the optimal number of clusters. First important result is that BIC seems more efficient than AIC and WSS to select the appropriate number of clusters (see example). The rule of thumb consists in increasing K until it no longer leads to an appreciable improvement of fit (i.e., to a decrease of BIC). In the most simple models (island models), BIC decreases until it reaches the optimal K, and then increases. In these cases, our rule amounts to choosing the lowest K. In other models such as stepping stones, the decrease of BIC often continues after the optimal K, but is much less steep.

An alternative approach is the automatic selection based on a fixed criterion. Note that, in any case, it is highly recommended to look at the graph of the BIC for different numbers of clusters as displayed during the interactive cluster selection. To use automated selection, set choose.n.clust to FALSE and specify the criterion you want to use, from the following values:

- "diffNgroup": differences between successive values of the summary statistics (by default, BIC) are splitted into two groups using a Ward's clustering method (see ?hclust), to differentiate sharp decrease from mild decreases or increases. The retained K is the one before the first group switch. Appears to work well for island/hierarchical models, and decently for isolation by distance models, albeit with some unstability. Can be impacted by an initial, very sharp decrease of the test statistics. IF UNSURE ABOUT THE CRITERION TO USE, USE THIS ONE.

- "min": the model with the minimum summary statistics (as specified by stat argument, BIC by default) is retained. Is likely to work for simple island model, using BIC. It is likely to fail in models relating to stepping stones, where the BIC always decreases (albeit by a small amount) as K increases. In general, this approach tends to over-estimate the number of clusters.

- "goesup": the selected model is the K after which increasing the number of clusters leads to increasing the summary statistics. Suffers from inaccuracy, since i) a steep decrease might follow a small 'bump' of increase of the statistics, and ii) increase might never happen, or happen after negligible decreases. Is likely to work only for clear-cut island models.

- "smoothNgoesup": a variant of "goesup", in which the summary statistics is first smoothed using a lowess approach. Is meant to be more accurate than "goesup" as it is less prone to stopping to small 'bumps' in the decrease of the statistics.

- "goodfit": another criterion seeking a good fit with a minimum number of clusters. This approach does not rely on differences between successive statistics, but on absolute fit. It selects the model with the smallest K so that the overall fit is above a given threshold.

Value

The class find.clusters is a list with the following components:

Kstat

a numeric vector giving the values of the summary statistics for the different values of K. Is NULL if n.clust was specified.

stat

a numeric value giving the value of the summary statistics for the retained model

grp

a factor giving group membership for each individual.

size

an integer vector giving the size of the different clusters.

Author(s)

Thibaut Jombart [email protected]

References

Jombart T, Devillard S and Balloux F (2010) Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. BMC Genetics 11:94. doi:10.1186/1471-2156-11-94

See Also

- dapc: implements the DAPC.

- scatter.dapc: graphics for DAPC.

- dapcIllus: dataset illustrating the DAPC and find.clusters.

- eHGDP: dataset illustrating the DAPC and find.clusters.

- kmeans: implementation of K-means in the stat package.

- dudi.pca: implementation of PCA in the ade4 package.

Examples

## Not run: 
## THIS ONE TAKES A FEW MINUTES TO RUN ## 
data(eHGDP)

## here, n.clust is specified, so that only on K value is used
grp <- find.clusters(eHGDP, max.n=30, n.pca=200, scale=FALSE,
n.clust=4) # takes about 2 minutes
names(grp)
grp$Kstat
grp$stat


## to try different values of k (interactive)
grp <- find.clusters(eHGDP, max.n=50, n.pca=200, scale=FALSE)

## and then, to plot BIC values:
plot(grp$Kstat, type="b", col="blue")



## ANOTHER SIMPLE EXAMPLE ## 
data(sim2pop) # this actually contains 2 pop

## DETECTION WITH BIC (clear result)
foo.BIC <- find.clusters(sim2pop, n.pca=100, choose=FALSE)
plot(foo.BIC$Kstat, type="o", xlab="number of clusters (K)", ylab="BIC",
col="blue", main="Detection based on BIC")
points(2, foo.BIC$Kstat[2], pch="x", cex=3)
mtext(3, tex="'X' indicates the actual number of clusters")


## DETECTION WITH AIC (less clear-cut)
foo.AIC <- find.clusters(sim2pop, n.pca=100, choose=FALSE, stat="AIC")
plot(foo.AIC$Kstat, type="o", xlab="number of clusters (K)",
ylab="AIC", col="purple", main="Detection based on AIC")
points(2, foo.AIC$Kstat[2], pch="x", cex=3)
mtext(3, tex="'X' indicates the actual number of clusters")


## DETECTION WITH WSS (less clear-cut)
foo.WSS <- find.clusters(sim2pop, n.pca=100, choose=FALSE, stat="WSS")
plot(foo.WSS$Kstat, type="o", xlab="number of clusters (K)", ylab="WSS
(residual variance)", col="red", main="Detection based on WSS")
points(2, foo.WSS$Kstat[2], pch="x", cex=3)
mtext(3, tex="'X' indicates the actual number of clusters")


## TOY EXAMPLE FOR GENLIGHT OBJECTS ##
x <- glSim(100,500,500)
x
plot(x)
grp <- find.clusters(x, n.pca = 100, choose = FALSE, stat = "BIC")
plot(grp$Kstat, type = "o", xlab = "number of clusters (K)",
     ylab = "BIC",
     main = "find.clusters on a genlight object\n(two groups)")

## End(Not run)

Identify mutations between DNA sequences

Description

The function findMutations identifies mutations (position and nature) of pairs of aligned DNA sequences. The function graphMutations does the same thing but plotting mutations on a directed graph.

Both functions are generics, but the only methods implemented in adegenet so far is for DNAbin objects.

Usage

findMutations(...)

## S3 method for class 'DNAbin'
findMutations(x, from=NULL, to=NULL, allcomb=TRUE, ...)

graphMutations(...)

## S3 method for class 'DNAbin'
graphMutations(x, from=NULL, to=NULL, allcomb=TRUE, plot=TRUE,
               curved.edges=TRUE, ...)

Arguments

x

a DNAbin object containing aligned sequences, as a matrix.

from

a vector indicating the DNA sequences from which mutations should be found. If NULL, all sequences are considered (i.e., 1:nrow(x)).

to

a vector indicating the DNA sequences to which mutations should be found. If NULL, all sequences are considered (i.e., 1:nrow(x)).

allcomb

a logical indicating whether all combinations of sequences (from and to) should be considered (TRUE, default), or not (FALSE).

plot

a logical indicating whether the graph should be plotted.

curved.edges

a logical indicating whether the edges of the graph should be curved.

...

further arguments to be passed to other methods. Used in graphMutations where it is passed to the plot method for igraph objects.

Value

For findMutations, a named list indicating the mutations from one sequence to another. For each comparison, a three-column matrix is provided, corresponding to the nucleotides in first and second sequence, and a summary of the mutation provided as: [position]:[nucleotide in first sequence]->[nucleotide in second sequence].

For graphMutations, a graph with the class igraph.

Author(s)

Thibaut Jombart [email protected].

See Also

The fasta2DNAbin to read fasta alignments with minimum RAM use.

Examples

## Not run: 
data(woodmouse)

## mutations between first 3 sequences
findMutations(woodmouse[1:3,])

## mutations from the first to sequences 2 and 3
findMutations(woodmouse[1:3,], from=1)

## same, graphical display
g <- graphMutations(woodmouse[1:3,], from=1)

## some manual checks
as.character(woodmouse)[1:3,35]
as.character(woodmouse)[1:3,36]
as.character(woodmouse)[1:3,106]


## End(Not run)

Genetic transitive graphs

Description

These functions are under development. Please email the author before using them for published work.

The function gengraph generates graphs based on genetic distances, so that pairs of entities (individuals or populations) are connected if and only if they are distant by less than a given threshold distance. Graph algorithms and classes from the igraph package are used.

gengraph is a generic function with methods for the following types of objects:
- matrix (only numeric data)
- dist
- genind objects (genetic markers, individuals)
- genpop objects (genetic markers, populations)
- DNAbin objects (DNA sequences)

Usage

gengraph(x, ...)

## S3 method for class 'matrix'
gengraph(x, cutoff=NULL, ngrp=NULL, computeAll=FALSE,
           plot=TRUE, show.graph=TRUE, col.pal=funky, truenames=TRUE,
           nbreaks=10, ...)

## S3 method for class 'dist'
gengraph(x, cutoff=NULL, ngrp=NULL, computeAll=FALSE,
           plot=TRUE, show.graph=TRUE, col.pal=funky, truenames=TRUE,
           nbreaks=10, ...)

## S3 method for class 'genind'
gengraph(x, cutoff=NULL, ngrp=NULL, computeAll=FALSE,
           plot=TRUE, show.graph=TRUE, col.pal=funky, truenames=TRUE,
           nbreaks=10, ...)

## S3 method for class 'genpop'
gengraph(x, cutoff=NULL, ngrp=NULL, computeAll=FALSE,
           plot=TRUE, show.graph=TRUE, col.pal=funky, method=1,
           truenames=TRUE, nbreaks=10, ...)

## S3 method for class 'DNAbin'
gengraph(x, cutoff=NULL, ngrp=NULL, computeAll=FALSE,
           plot=TRUE, show.graph=TRUE, col.pal=funky, truenames=TRUE,
           nbreaks=10, ...)

Arguments

x

a matrix, dist, genind, genpop, or DNAbin object. For matrix and dist, the object represents pairwise (by default, Hamming) distances between considered individuals.

cutoff

a numeric value indicating the cutoff point, i.e. the distance at which two entities are no longer connected in the garph produced by the method.

ngrp

an integer indicating the number of groups to be looked for. A message is issued if this exact number could not be found.

computeAll

a logical stating whether to investigate solutions for every (integer) cutoff point; defaults to FALSE.

plot

a logical indicating whether plots should be drawn; defaults to TRUE; this operation can take time for large, highly-connected graphs.

show.graph

a logical indicating whether the found graph should be drawn, only used in the interactive mode; this operation can take time for large, highly-connected graphs; defaults to FALSE.

col.pal

a color palette used to define group colors.

method

an integer ranging from 1 to 6 indicating the type of method to be used to derive a matrix of pairwise distances between populations; values from 1 to 5 are passed to the function dist.genpop; other values are not supported.

truenames

a logical indicating whether original labels should be used for plotting (TRUE), as opposed to indices of sequences (FALSE).

nbreaks

an integer indicating the number of breaks used by the heuristic when seeking an exact number of groups.

...

further arguments to be used by other functions; currently not used.

Value

The class gengraph is a list with the following components:

graph

a graph of class igraph.

clust

a list containing group information: $membership: an integer giving group membership; $csize: the size of each cluster; $no: the number of clusters

cutoff

the value used as a cutoff point

col

the color used to plot each group.

Author(s)

Original idea by Anne Cori and Christophe Fraser. Implementation by Thibaut Jombart [email protected].

See Also

The igraph package.

Examples

if(require(ape)){
    data(woodmouse)
    g <- gengraph(woodmouse, cutoff=5)
    g
    plot(g$graph)

}

adegenet formal class (S4) for individual genotypes

Description

The S4 class genind is used to store individual genotypes.
It contains several components described in the 'slots' section).
The summary of a genind object invisibly returns a list of component. The function .valid.genind is for internal use. The function genind creates a genind object from a valid table of alleles corresponding to the @tab slot. Note that as in other S4 classes, slots are accessed using @ instead of $.

Slots

tab:

(accessor: tab) matrix integers containing genotypes data for individuals (in rows) for all alleles (in columns). The table differs depending on the @type slot:
- 'codom': values are numbers of alleles, summing up to the individuals' ploidies.
- 'PA': values are presence/absence of alleles.
In all cases, rows and columns are given generic names.

loc.fac:

(accessor: locFac) locus factor for the columns of tab

loc.n.all:

(accessor: nAll) integer vector giving the number of observed alleles per locus (see note)

all.names:

(accessor: alleles) list having one component per locus, each containing a character vector of allele names

ploidy:

(accessor: ploidy) an integer vector indicating the degree of ploidy of the genotypes. Beware: 2 is not an integer, but 2L or as.integer(2) is.

type:

a character string indicating the type of marker: 'codom' stands for 'codominant' (e.g. microstallites, allozymes); 'PA' stands for 'presence/absence' (e.g. AFLP).

call:

the matched call

strata:

(accessor: strata) (optional) data frame giving levels of population stratification for each individual

hierarchy:

(accessor: hier) (optional, currently unused) a hierarchical formula defining the hierarchical levels in the @@strata slot.

pop:

(accessor: pop) (optional) factor giving the population of each individual

other:

(accessor: other) (optional) a list containing other information

Note:

The loc.n.all slot will reflect the number of columns per locus that contain at least one observation. This means that the sum of the this vector will not necessarily equal the number of columns in the data unless you use drop = TRUE when subsetting.

Extends

Class "gen", directly. Class "indInfo", directly.

Methods

names

signature(x = "genind"): give the names of the components of a genind object

print

signature(x = "genind"): prints a genind object

show

signature(object = "genind"): shows a genind object (same as print)

summary

signature(object = "genind"): summarizes a genind object, invisibly returning its content or suppress printing of auxiliary information by specifying verbose = FALSE

Author(s)

Thibaut Jombart [email protected]

See Also

as.genind, genind2genpop, genpop, import2genind, read.genetix, read.genepop, read.fstat

Related classes:
- genpop for storing data per populations

- genlight for an efficient storage of binary SNPs genotypes

Examples

showClass("genind")

obj <- read.genetix(system.file("files/nancycats.gtx",package="adegenet"))
obj
validObject(obj)
summary(obj)

## Not run: 
# test inter-colonies structuration
if(require(hierfstat)){
gtest <- gstat.randtest(obj,nsim=99)
gtest
plot(gtest)
}

# perform a between-class PCA
pca1 <- dudi.pca(scaleGen(obj, NA.method="mean"),scannf=FALSE,scale=FALSE)
pcabet1 <- between(pca1,obj@pop,scannf=FALSE)
pcabet1

s.class(pcabet1$ls,obj@pop,sub="Inter-class PCA",possub="topleft",csub=2)
add.scatter.eig(pcabet1$eig,2,xax=1,yax=2)


## End(Not run)

Convert a genind object to a data.frame.

Description

The function genind2df converts a genind back to a data.frame of raw allelic data.

Usage

genind2df(x, pop = NULL, sep = "", usepop = TRUE, oneColPerAll = FALSE)

Arguments

x

a genind object

pop

an optional factor giving the population of each individual.

sep

a character string separating alleles. See details.

usepop

a logical stating whether the population (argument pop or x@pop should be used (TRUE, default) or not (FALSE)).

oneColPerAll

a logical stating whether or not alleles should be split into columns (defaults to FALSE). This will only work with data with consistent ploidies.

Value

a data.frame of raw allelic data, with individuals in rows and loci in column

Author(s)

Thibaut Jombart [email protected]

See Also

df2genind, import2genind, read.genetix, read.fstat, read.structure

Examples

## simple example
df <- data.frame(locusA=c("11","11","12","32"),
locusB=c(NA,"34","55","15"),locusC=c("22","22","21","22"))
row.names(df) <- .genlab("genotype",4)
df

obj <- df2genind(df, ploidy=2, ncode=1)
obj
obj@tab


## converting a genind as data.frame
genind2df(obj)
genind2df(obj, sep="/")

Conversion from a genind to a genpop object

Description

The function genind2genpop converts genotypes data (genind) into alleles counts per population (genpop).

Usage

genind2genpop(
  x,
  pop = NULL,
  quiet = FALSE,
  process.other = FALSE,
  other.action = mean
)

Arguments

x

an object of class genind.

pop

a factor giving the population of each genotype in 'x' OR a formula specifying which strata are to be used when converting to a genpop object. If none provided, population factors are sought in x@pop, but if given, the argument prevails on x@pop.

quiet

logical stating whether a conversion message must be printed (TRUE,default) or not (FALSE).

process.other

a logical indicating whether the @other slot should be processed (see details).

other.action

a function to be used when processing the @other slot. By default, 'mean' is used.

Details

=== 'missing' argument ===
The values of the 'missing' argument in genind2genpop have the following effects:
- "NA": if all genotypes of a population for a given allele are missing, count value will be NA

- "0": if all genotypes of a population for a given allele are missing, count value will be 0

- "chi2": if all genotypes of a population for a given allele are missing, count value will be that of a theoretical count in of a Chi-squared test. This is obtained by the product of the margins sums divided by the total number of alleles.

=== processing the @other slot ===
Essentially, genind2genpop is about aggregating data per population. The function can do the same for all numeric items in the @other slot provided they have the same length (for vectors) or the same number of rows (matrix-like objects) as the number of genotypes. When the case is encountered and if process.other is TRUE, then these objects are processed using the function defined in other.action per population. For instance, spatial coordinates of genotypes would be averaged to obtain population coordinates.

Value

A genpop object. The component @other in 'x' is passed to the created genpop object.

Author(s)

Thibaut Jombart [email protected]

See Also

genind, genpop

Examples

## simple conversion
data(nancycats)
nancycats
catpop <- genind2genpop(nancycats)
catpop
summary(catpop)

## processing the @other slot
data(sim2pop)
sim2pop$other$foo <- letters
sim2pop
dim(sim2pop$other$xy) # matches the number of genotypes
sim2pop$other$foo # does not match the number of genotypes

obj <- genind2genpop(sim2pop, process.other=TRUE)
obj$other # the new xy is the populations' centre

pch <- as.numeric(pop(sim2pop))
col <- pop(sim2pop)
levels(col) <- c("blue","red")
col <- as.character(col)
plot(sim2pop$other$xy, pch=pch, col=col)
text(obj$other$xy, lab=row.names(obj$other$xy), col=c("blue","red"), cex=2, font=2)
## Not run: 
data(microbov)
strata(microbov) <- data.frame(other(microbov))
summary(genind2genpop(microbov)) # Conversion based on population factor
summary(genind2genpop(microbov, ~coun)) # Conversion based on country
summary(genind2genpop(microbov, ~coun/spe)) # Conversion based on country and species


## End(Not run)

Auxiliary functions for genlight objects

Description

These functions provide facilities for usual computations using genlight objects. When ploidy varies across individuals, the outputs of these functions depend on whether the information units are individuals, or alleles within individuals (see details).

These functions are:

- glSum: computes the sum of the number of second allele in each SNP.

- glNA: computes the number of missing values in each SNP.

- glMean: computes the mean number of second allele in each SNP.

- glVar: computes the variance of the number of second allele in each SNP.

- glDotProd: computes dot products between (possibly centred/scaled) vectors of individuals - uses compiled C code - used by glPca.

Usage

glSum(x, alleleAsUnit = TRUE, useC = FALSE)
glNA(x, alleleAsUnit = TRUE)
glMean(x, alleleAsUnit = TRUE)
glVar(x, alleleAsUnit = TRUE)
glDotProd(x, center = FALSE, scale = FALSE, alleleAsUnit = FALSE,
                parallel = FALSE, n.cores = NULL)

Arguments

x

a genlight object

alleleAsUnit

a logical indicating whether alleles are considered as units (i.e., a diploid genotype equals two samples, a triploid, three, etc.) or whether individuals are considered as units of information.

center

a logical indicating whether SNPs should be centred to mean zero.

scale

a logical indicating whether SNPs should be scaled to unit variance.

useC

a logical indicating whether compiled C code should be used (TRUE) or not (FALSE, default).

parallel

a logical indicating whether multiple cores -if available- should be used for the computations (TRUE, default), or not (FALSE); requires the package parallel to be installed (see details); this option cannot be used alongside useCoption.

n.cores

if parallel is TRUE, the number of cores to be used in the computations; if NULL, then the maximum number of cores available on the computer is used.

Details

=== On the unit of information ===

In the cases where individuals can have different ploidy, computation of sums, means, etc. of allelic data depends on what we consider as a unit of information.

To estimate e.g. allele frequencies, unit of information can be considered as the allele, so that a diploid genotype contains two samples, a triploid individual, three samples, etc. In such a case, all computations are done directly on the number of alleles. This corresponds to alleleAsUnit = TRUE.

However, when the focus is put on studying differences/similarities between individuals, the unit of information is the individual, and all genotypes possess the same information no matter what their ploidy is. In this case, computations are made after standardizing individual genotypes to relative allele frequencies. This corresponds to alleleAsUnit = FALSE.

Note that when all individuals have the same ploidy, this distinction does not hold any more.

Value

A numeric vector containing the requested information.

Author(s)

Thibaut Jombart [email protected]

See Also

- genlight: class of object for storing massive binary SNP data.

- dapc: Discriminant Analysis of Principal Components.

- glPca: PCA for genlight objects.

- glSim: a simple simulator for genlight objects.

- glPlot: plotting genlight objects.

Examples

## Not run: 
x <- new("genlight", list(c(0,0,1,1,0), c(1,1,1,0,0,1), c(2,1,1,1,1,NA)))
x
as.matrix(x)
ploidy(x)

## compute statistics - allele as unit ##
glNA(x)
glSum(x)
glMean(x)

## compute statistics - individual as unit ##
glNA(x, FALSE)
glSum(x, FALSE)
glMean(x, FALSE)

## explanation: data are taken as relative frequencies
temp <- as.matrix(x)/ploidy(x)
apply(temp,2, function(e) sum(is.na(e))) # NAs
apply(temp,2,sum, na.rm=TRUE) # sum
apply(temp,2,mean, na.rm=TRUE) # mean

## End(Not run)

Formal class "genlight"

Description

The class genlight is a formal (S4) class for storing a genotypes of binary SNPs in a compact way, using a bit-level coding scheme. This storage is most efficient with haploid data, where the memory taken to represent data can be reduced more than 50 times. However, genlight can be used for any level of ploidy, and still remain an efficient storage mode.

A genlight object can be constructed from vectors of integers giving the number of the second allele for each locus and each individual (see 'Objects of the class genlight' below).

genlight stores multiple genotypes. Each genotype is stored as a SNPbin object.

Details

=== On the subsetting using [ ===

The function [ accepts the following extra arguments:

treatOther

a logical stating whether elements of the @other slot should be treated as well (TRUE), or not (FALSE). If treated, elements of the list are examined for a possible match of length (vectors, lists) or number of rows (matrices, data frames) with the number of individuals. Those who match are subsetted accordingly. Others are left as is, issuing a warning unless the argument quiet is set to TRUE.

quiet

a logical indicating whether warnings should be issued when trying to subset components of the @other slot which do not match the number of individuals (TRUE), or not (FALSE, default).

...

further arguments passed to the genlight constructor.

Objects from the class genlight

genlight objects can be created by calls to new("genlight", ...), where '...' can be the following arguments:

gen

input genotypes, where each genotype is coded as a vector of numbers of the second allele. If a list, each slot of the list correspond to an individual; if a matrix or a data.frame, rows correspond to individuals and columns to SNPs. If individuals or loci are named in the input, these names will we stored in the produced object. All individuals are expected to have the same number of SNPs. Shorter genotypes are completed with NAs, issuing a warning.

ploidy

an optional vector of integers indicating the ploidy of the genotypes. Genotypes can therefore have different ploidy. If not provided, ploidy will be guessed from the data (as the maximum number of second alleles in each individual).

ind.names

an optional vector of characters giving the labels of the genotypes.

loc.names

an optional vector of characters giving the labels of the SNPs.

loc.all

an optional vector of characters indicating the alleles of each SNP; for each SNP, alleles must be coded by two letters separated by '/', e.g. 'a/t' is valid, but 'a t' or 'a |t' are not.

chromosome

an optional factor indicating the chromosome to which each SNP belongs.

position

an optional vector of integers indicating the position of the SNPs.

other

an optional list storing miscellaneous information.

Slots

The following slots are the content of instances of the class genlight; note that in most cases, it is better to retrieve information via accessors (see below), rather than by accessing the slots manually.

gen:

a list of genotypes stored as SNPbin objects.

n.loc:

an integer indicating the number of SNPs of the genotype.

ind.names:

a vector of characters indicating the names of genotypes.

loc.names:

a vector of characters indicating the names of SNPs.

loc.all:

a vector of characters indicating the alleles of each SNP.

chromosome:

an optional factor indicating the chromosome to which each SNP belongs.

position:

an optional vector of integers indicating the position of the SNPs.

ploidy:

a vector of integers indicating the ploidy of each individual.

pop:

a factor indicating the population of each individual.

strata:

a data frame containing different levels of population definition. (For methods, see addStrata and setPop)

hierarchy:

a hierarchical formula defining the hierarchical levels in the @@strata slot.

other:

a list containing other miscellaneous information.

Methods

Here is a list of methods available for genlight objects. Most of these methods are accessors, that is, functions which are used to retrieve the content of the object. Specific manpages can exist for accessors with more than one argument. These are indicated by a '*' symbol next to the method's name. This list also contains methods for conversion from genlight to other classes.

[

signature(x = "genlight"): usual method to subset objects in R. Is to be applied as if the object was a matrix where genotypes were rows and SNPs were columns. Indexing can be done via vectors of signed integers or of logicals. See details for extra supported arguments.

show

signature(x = "genlight"): printing of the object.

$

signature(x = "genlight"): similar to the @ operator; used to access the content of slots of the object.

$<-

signature(x = "genlight"): similar to the @ operator; used to replace the content of slots of the object.

tab

signature(x = "genlight"): returns a table of allele counts (see tab; additional arguments are freq, a logical stating if relative frequencies should be returned (use for varying ploidy), and NA.method, a character indicating if missing values should be replaced by the mean frequency("mean"), or left as is ("asis").

nInd

signature(x = "genlight"): returns the number of individuals in the object.

nPop

signature(x = "genlight"): returns the number of populations in the object.

nLoc

signature(x = "genlight"): returns the number of SNPs in the object.

dim

signature(x = "genlight"): returns the number of individuals and SNPs in the object, respectively.

names

signature(x = "genlight"): returns the names of the slots of the object.

indNames

signature(x = "genlight"): returns the names of the individuals, if provided when the object was constructed.

indNames<-

signature(x = "genlight"): sets the names of the individuals using a character vector of length nInd(x).

popNames

signature(x = "genlight"): returns the names of the populations, if provided when the object was constructed.

popNames<-

signature(x = "genlight"): sets the names of the populations using a character vector of length nPop(x).

locNames

signature(x = "genlight"): returns the names of the loci, if provided when the object was constructed.

locNames<-

signature(x = "genlight"): sets the names of the SNPs using a character vector of length nLoc(x).

ploidy

signature(x = "genlight"): returns the ploidy of the genotypes.

ploidy<-

signature(x = "genlight"): sets the ploidy of the individuals using a vector of integers of size nInd(x); if a single value is provided, the same ploidy is assumed for all individuals.

NA.posi

signature(x = "genlight"): returns the indices of missing values (NAs) as a list with one vector of integer for each individual.

alleles

signature(x = "genlight"): returns the names of the alleles of each SNPs, if provided when the object was constructed.

alleles<-

signature(x = "genlight"): sets the names of the alleles of each SNPs using a character vector of length nLoc(x); for each SNP, two alleles must be provided, separated by a "/", e.g. 'a/t', 'c/a', etc.

chromosome

signature(x = "genlight"): returns a factor indicating the chromosome of each SNPs, or NULL if the information is missing.

chromosome<-

signature(x = "genlight"): sets the chromosome to which SNPs belong using a factor of length nLoc(x).

chr

signature(x = "genlight"): shortcut for chromosome.

chr<-

signature(x = "genlight"): shortcut for chromosome<-.

position

signature(x = "genlight"): returns an integer vector indicating the position of each SNPs, or NULL if the information is missing.

position<-

signature(x = "genlight"): sets the positions of the SNPs using an integer vector of length nLoc(x).

pop

signature(x = "genlight"): returns a factor indicating the population of each individual, if provided when the object was constructed.

pop<-

signature(x = "genlight"): sets the population of each individual using a factor of length nInd(x).

other

signature(x = "genlight"): returns the content of the slot @other.

other<-

signature(x = "genlight"): sets the content of the slot @other.

as.matrix

signature(x = "genlight"): converts a genlight object into a matrix of integers, with individuals in rows and SNPs in columns. The S4 method 'as' can be used as well (e.g. as(x, "matrix")).

as.data.frame

signature(x = "genlight"): same as as.matrix.

as.list

signature(x = "genlight"): converts a genlight object into a list of genotypes coded as vector of integers (numbers of second allele). The S4 method 'as' can be used as well (e.g. as(x, "list")).

cbind

signature(x = "genlight"): merges several genlight objects by column, i.e. regroups data of identical individuals genotyped for different SNPs.

rbind

signature(x = "genlight"): merges several genlight objects by row, i.e. regroups data of different individuals genotyped for the same SNPs.

Author(s)

Thibaut Jombart ([email protected])
Zhian N. Kamvar ([email protected])

See Also

Related class:
- SNPbin, for storing individual genotypes of binary SNPs

- genind, for storing other types of genetic markers.

Examples

## Not run: 
## TOY EXAMPLE ##
## create and convert data
dat <- list(toto=c(1,1,0,0), titi=c(NA,1,1,0), tata=c(NA,0,3, NA))
x <- new("genlight", dat)
x

## examine the content of the object
names(x)
x@gen
x@gen[[1]]@snp # bit-level coding for first individual

## conversions
as.list(x)
as.matrix(x)

## round trips - must return TRUE
identical(x, new("genlight", as.list(x))) # list
identical(x, new("genlight", as.matrix(x))) # matrix
identical(x, new("genlight", as.data.frame(x))) # data.frame

## test subsetting
x[c(1,3)] # keep individuals 1 and 3
as.list(x[c(1,3)])
x[c(1,3), 1:2] # keep individuals 1 and 3, loci 1 and 2
as.list(x[c(1,3), 1:2])
x[c(TRUE,FALSE), c(TRUE,TRUE,FALSE,FALSE)] # same, using logicals
as.list(x[c(TRUE,FALSE), c(TRUE,TRUE,FALSE,FALSE)])


## REAL-SIZE EXAMPLE ##
## 50 genotypes of 1,000,000 SNPs
dat <- lapply(1:50, function(i) sample(c(0,1,NA), 1e6, prob=c(.5, .49, .01), replace=TRUE))
names(dat) <- paste("indiv", 1:length(dat))
print(object.size(dat), unit="aut") # size of the original data

x <- new("genlight", dat) # conversion
x
print(object.size(x), unit="au") # size of the genlight object
object.size(dat)/object.size(x) # conversion efficiency



#### cbind, rbind ####
a <- new("genlight", list(toto=rep(1,10), tata=rep(c(0,1), each=5), titi=c(NA, rep(1,9)) ))

ara <- rbind(a,a)
ara
as.matrix(ara)

aca <- cbind(a,a)
aca
as.matrix(aca)


#### subsetting @other ####
x <- new("genlight", list(a=1,b=0,c=1), other=list(1:3, letters,data.frame(2:4)))
x
other(x)
x[2:3]
other(x[2:3])
other(x[2:3, treatOther=FALSE])


#### seppop ####
pop(x) # no population info
pop(x) <- c("pop1","pop1", "pop2") # set population memberships
pop(x)
seppop(x)

## End(Not run)

adegenet formal class (S4) for allele counts in populations

Description

An object of class genpop contain alleles counts for several loci.
It contains several components (see 'slots' section).
Such object is obtained using genind2genpop which converts individuals genotypes of known population into a genpop object. Note that the function summary of a genpop object returns a list of components. Note that as in other S4 classes, slots are accessed using @ instead of $.

Slots

tab:

matrix of alleles counts for each combinaison of population (in rows) and alleles (in columns).

loc.fac:

locus factor for the columns of tab

loc.n.all:

integer vector giving the number of alleles per locus

all.names:

list having one component per locus, each containing a character vector of alleles names

call:

the matched call

ploidy:

an integer indicating the degree of ploidy of the genotypes. Beware: 2 is not an integer, but as.integer(2) is.

type:

a character string indicating the type of marker: 'codom' stands for 'codominant' (e.g. microstallites, allozymes); 'PA' stands for 'presence/absence' (e.g. AFLP).

other:

(optional) a list containing other information

Extends

Class "gen", directly. Class "popInfo", directly.

Methods

names

signature(x = "genpop"): give the names of the components of a genpop object

print

signature(x = "genpop"): prints a genpop object

show

signature(object = "genpop"): shows a genpop object (same as print)

summary

signature(object = "genpop"): summarizes a genpop object, invisibly returning its content or suppress printing of auxiliary information by specifying verbose = FALSE

Author(s)

Thibaut Jombart [email protected]

See Also

as.genpop, is.genpop,makefreq, genind, import2genind, read.genetix, read.genepop, read.fstat

Examples

obj1 <- import2genind(system.file("files/nancycats.gen",
package="adegenet"))
obj1


obj2 <- genind2genpop(obj1)
obj2

## Not run: 
data(microsatt)
# use as.genpop to convert convenient count tab to genpop
obj3 <- as.genpop(microsatt$tab)
obj3

all(obj3@tab==microsatt$tab)

# perform a correspondance analysis
obj4 <- genind2genpop(obj1,missing="chi2")
ca1 <- dudi.coa(as.data.frame(obj4@tab),scannf=FALSE)
s.label(ca1$li,sub="Correspondance Analysis",csub=2)
add.scatter.eig(ca1$eig,2,xax=1,yax=2,posi="top")


## End(Not run)

Global and local tests

Description

These two Monte Carlo tests are used to assess the existence of global and local spatial structures. They can be used as an aid to interprete global and local components of spatial Principal Component Analysis (sPCA).

They rely on the decomposition of a data matrix X into global and local components using multiple regression on Moran's Eigenvector Maps (MEMs). They require a data matrix (X) and a list of weights derived from a connection network. X is regressed onto global MEMs (U+) in the global test and on local ones (U-) in the local test. One mean R2R^2 is obtained for each MEM, the k highest being summed to form the test statistic.

The reference distribution of these statistics are obtained by randomly permuting the rows of X.

Usage

global.rtest(X, listw, k = 1, nperm = 499)
local.rtest(X, listw, k = 1, nperm = 499)

Arguments

X

a data matrix, with variables in columns

listw

a list of weights of class listw. Can be obtained easily using the function chooseCN.

k

integer: the number of highest R2R^2 summed to form the test statistics

nperm

integer: the number of randomisations to be performed.

Details

This test is purely R code. A C or C++ version will be developped soon.

Value

An object of class randtest.

Author(s)

Thibaut Jombart [email protected]

References

Jombart, T., Devillard, S., Dufour, A.-B. and Pontier, D. Revealing cryptic spatial patterns in genetic variability by a new multivariate method. Heredity, 101, 92–103.

See Also

chooseCN, spca, monmonier

Examples

## Not run: 
 data(sim2pop)
if(require(spdep)){
cn <- chooseCN(sim2pop@other$xy,ask=FALSE,type=1,plot=FALSE,res="listw")

# global test
Gtest <- global.rtest(sim2pop@tab,cn)
Gtest

# local test
Ltest <- local.rtest(sim2pop@tab,cn)
Ltest
}

## End(Not run)

Principal Component Analysis for genlight objects

Description

These functions implement Principal Component Analysis (PCA) for massive SNP datasets stored as genlight object. This implementation has the advantage of never representing to complete data matrix, therefore making huge economies in terms of rapid access memory (RAM). When the parallel package is available, glPca uses multiple-core ressources for more efficient computations. glPca returns lists with the class glPca (see 'value').

Other functions are defined for objects of this class:

- print: prints the content of a glPca object.

- scatter: produces scatterplots of principal components, with a screeplot of eigenvalues as inset.

- loadingplot: plots the loadings of the analysis for one given axis, using an adapted version of the generic function loadingplot.

Usage

glPca(x, center = TRUE, scale = FALSE, nf = NULL, loadings = TRUE, 
    alleleAsUnit = FALSE, useC = TRUE, parallel = FALSE,
  n.cores = NULL, returnDotProd=FALSE, matDotProd=NULL)

## S3 method for class 'glPca'
print(x, ...)

## S3 method for class 'glPca'
scatter(x, xax = 1, yax = 2, posi = "bottomleft", bg = "white", 
    ratio = 0.3, label = rownames(x$scores), clabel = 1, xlim = NULL, 
    ylim = NULL, grid = TRUE, addaxes = TRUE, origin = c(0, 0), 
    include.origin = TRUE, sub = "", csub = 1, possub = "bottomleft", 
    cgrid = 1, pixmap = NULL, contour = NULL, area = NULL, ...)

## S3 method for class 'glPca'
loadingplot(x, at=NULL, threshold=NULL, axis=1,
    fac=NULL, byfac=FALSE, lab=rownames(x$loadings), cex.lab=0.7, cex.fac=1,
    lab.jitter=0, main="Loading plot", xlab="SNP positions",
    ylab="Contributions", srt = 90, adj = c(0, 0.5), ...)

Arguments

x

for glPca, a genlight object; for print, scatter, and loadingplot, a glPca object.

center

a logical indicating whether the numbers of alleles should be centered; defaults to TRUE

scale

a logical indicating whether the numbers of alleles should be scaled; defaults to FALSE

nf

an integer indicating the number of principal components to be retained; if NULL, a screeplot of eigenvalues will be displayed and the user will be asked for a number of retained axes.

loadings

a logical indicating whether loadings of the alleles should be computed (TRUE, default), or not (FALSE). Vectors of loadings are not always useful, and can take a large amount of RAM when millions of SNPs are considered.

alleleAsUnit

a logical indicating whether alleles are considered as units (i.e., a diploid genotype equals two samples, a triploid, three, etc.) or whether individuals are considered as units of information.

useC

a logical indicating whether compiled C code should be used for faster computations; this option cannot be used alongside parallel option.

parallel

a logical indicating whether multiple cores -if available- should be used for the computations (TRUE), or not (FALSE, default); requires the package parallel to be installed (see details); this option cannot be used alongside useCoption.

n.cores

if parallel is TRUE, the number of cores to be used in the computations; if NULL, then the maximum number of cores available on the computer is used.

returnDotProd

a logical indicating whether the matrix of dot products between individuals should be returned (TRUE) or not (FALSE, default).

matDotProd

an optional matrix of dot products between individuals, NULL by default. This option is used internally to speed up computation time when re-running the same PCA several times. Leave this argument as NULL unless you really know what you are doing.

...

further arguments to be passed to other functions.

xax, yax

integers specifying which principal components should be shown in x and y axes.

posi, bg, ratio

arguments used to customize the inset in scatterplots of glPca results. See add.scatter documentation in the ade4 package for more details.

label, clabel, xlim, ylim, grid, addaxes, origin, include.origin, sub, csub, possub, cgrid, pixmap, contour, area

arguments passed to s.class; see ?s.label for more information

at

an optional numeric vector giving the abscissa at which loadings are plotted. Useful when variates are SNPs with a known position in an alignement.

threshold

a threshold value above which values of x are identified. By default, this is the third quartile of x.

axis

an integer indicating the column of x to be plotted; used only if x is a matrix-like object.

fac

a factor defining groups of SNPs.

byfac

a logical stating whether loadings should be averaged by groups of SNPs, as defined by fac.

lab

a character vector giving the labels used to annotate values above the threshold.

cex.lab

a numeric value indicating the size of annotations.

cex.fac

a numeric value indicating the size of annotations for groups of observations.

lab.jitter

a numeric value indicating the factor of randomisation for the position of annotations. Set to 0 (by default) implies no randomisation.

main

the main title of the figure.

xlab

the title of the x axis.

ylab

the title of the y axis.

srt

rotation of the labels; see ?text.

adj

adjustment of the labels; see ?text.

Details

=== Using multiple cores ===

Most recent machines have one or several processors with multiple cores. R processes usually use one single core. The package parallel allows for parallelizing some computations on multiple cores, which can decrease drastically computational time.

Lastly, note that using compiled C code (useC=TRUE)is an alternative for speeding up computations, but cannot be used together with the parallel option.

Value

=== glPca objects ===

The class glPca is a list with the following components:

call

the matched call.

eig

a numeric vector of eigenvalues.

scores

a matrix of principal components, containing the coordinates of each individual (in row) on each principal axis (in column).

loadings

(optional) a matrix of loadings, containing the loadings of each SNP (in row) for each principal axis (in column).

-

=== other outputs ===

Other functions have different outputs:
- scatter return the matched call.
- loadingplot returns information about the most contributing SNPs (see loadingplot.default)

Author(s)

Thibaut Jombart [email protected]

See Also

- genlight: class of object for storing massive binary SNP data.

- glSim: a simple simulator for genlight objects.

- glPlot: plotting genlight objects.

- dapc: Discriminant Analysis of Principal Components.

Examples

## Not run: 
## simulate a toy dataset
x <- glSim(50,4e3, 50, ploidy=2)
x
plot(x)

## perform PCA
pca1 <- glPca(x, nf=2)

## plot eigenvalues
barplot(pca1$eig, main="eigenvalues", col=heat.colors(length(pca1$eig)))

## basic plot
scatter(pca1, ratio=.2)

## plot showing groups
s.class(pca1$scores, pop(x), col=colors()[c(131,134)])
add.scatter.eig(pca1$eig,2,1,2)

## End(Not run)

Plotting genlight objects

Description

genlight object can be plotted using the function glPlot, which is also used as the dedicated plot method. These functions relie on image to represent SNPs data. More specifically, colors are used to represent the number of second allele for each locus and individual.

Usage

glPlot(x, col=NULL, legend=TRUE, posi="bottomleft", bg=rgb(1,1,1,.5),...)

## S4 method for signature 'genlight'
plot(x, y=NULL, col=NULL, legend=TRUE, posi="bottomleft", bg=rgb(1,1,1,.5),...)

Arguments

x

a genlight object.

col

an optional color vector; the first value corresponds to 0 alleles, the last value corresponds to the ploidy level of the data. Therefore, the vector should have a length of (ploidy(x)+1).

legend

a logical indicating whether a legend should be added to the plot.

posi

a character string indicating where the legend should be positioned. Can be any concatenation of "bottom"/"top" and "left"/"right".

bg

a color used as a background for the legend; by default, transparent white is used; this may not be supported on some devices, and therefore background should be specified (e.g. bg="white").

...

further arguments to be passed to image.

y

ununsed argument, present for compatibility with the plot generic.

Author(s)

Thibaut Jombart [email protected]

See Also

- genlight: class of object for storing massive binary SNP data.

- glSim: a simple simulator for genlight objects.

- glPca: PCA for genlight objects.

Examples

## Not run: 
## simulate data
x <- glSim(100, 1e3, n.snp.struc=100, ploid=2)

## default plot
glPlot(x)
plot(x) # identical plot

## disable legend
plot(x, leg=FALSE)

## use other colors
plot(x, col=heat.colors(3), bg="white")

## End(Not run)

Simulation of simple genlight objects

Description

The function glSim simulates simple SNP data with the possibility of contrasted structures between two groups as well as background ancestral population structure. Returned objects are instances of the class genlight.

Usage

glSim(n.ind, n.snp.nonstruc, n.snp.struc = 0, grp.size = c(0.5, 0.5), k = NULL,
                    pop.freq = NULL, ploidy = 1, alpha = 0, parallel = FALSE,
                    LD = TRUE, block.minsize = 10, block.maxsize = 1000, theta = NULL,
                    sort.pop = FALSE, ...)

Arguments

n.ind

an integer indicating the number of individuals to be simulated.

n.snp.nonstruc

an integer indicating the number of non-structured SNPs to be simulated; for these SNPs, all individuals are drawn from the same binomial distribution.

n.snp.struc

an integer indicating the number of structured SNPs to be simulated; for these SNPs, different binomial distributions are used for the two simulated groups; frequencies of the derived alleles in groups A and B are built to differ (see details).

grp.size

a vector of length 2 specifying the proportions of the two phenotypic groups (must sum to 1). By default, both groups have the same size.

k

an integer specifying the number of ancestral populations to be generated.

pop.freq

a vector of length k specifying the proportions of the k ancestral populations (must sum to 1). If, as by default, pop.freq is null, and k is non-null, pop.freq will be the result of random sampling into k population groups.

ploidy

an integer indicating the ploidy of the simulated genotypes.

alpha

asymmetry parameter: a numeric value between 0 and 0.5, used to enforce allelic differences between the groups. Differences between groups are strongest when alpha = 0.5 and weakest when alpha = 0 (see details).

parallel

a logical indicating whether multiple cores should be used in generating the simulated data (TRUE). This option can reduce the amount of computational time required to simulate the data, but is not supported on Windows.

LD

a logical indicating whether loci should be displaying linkage disequilibrium (TRUE) or be generated independently (FALSE, default). When set to TRUE, data are generated by blocks of correlated SNPs (see details).

block.minsize

an optional integer indicating the minimum number of SNPs to be handled at a time during the simulation of linked SNPs (when LD=TRUE. Increasing the minimum block size will increase the RAM requirement but decrease the amount of computational time required to simulate the genotypes.

block.maxsize

an optional integer indicating the maximum number of SNPs to be handled at a time during the simulation of linked SNPs. Note: if LD blocks of equal size are desired, set block.minsize = block.maxsize.

theta

an optional numeric value between 0 and 0.5 specifying the extent to which linkage should be diluted. Linkage is strongest when theta = 0 and weakest when theta = 0.5.

sort.pop

a logical specifying whether individuals should be ordered by ancestral population (sort.pop=TRUE) or phenotypic population (sort.pop=FALSE).

...

arguments to be passed to the genlight constructor.

Details

=== Allele frequencies in contrasted groups ===

When n.snp.struc is greater than 0, some SNPs are simulated in order to differ between groups (noted 'A' and 'B'). Different patterns between groups are achieved by using different frequencies of the second allele for A and B, denoted pAp_A and pBp_B. For a given SNP, pAp_A is drawn from a uniform distribution between 0 and (0.5 - alpha). pBp_B is then computed as 1 - pAp_A. Therefore, differences between groups are mild for alpha=0, and total for alpha = 0.5.

=== Linked or independent loci ===

Independent loci (LD=FALSE) are simulated using the standard binomial distribution, with randomly generated allele frequencies. Linked loci (LD=FALSE) are trickier towe need to simulate discrete variables with pre-defined correlation structure.

Here, we first generate deviates from multivariate normal distributions with randomly generated correlation structures. These variables are then discretized using the quantiles of the distribution. Further improvement of the procedure will aim at i) specifying the strength of the correlations between blocks of alleles and ii) enforce contrasted structures between groups.

Value

A genlight object.

Author(s)

Caitlin Collins [email protected], Thibaut Jombart [email protected]

See Also

- genlight: class of object for storing massive binary SNP data.

- glPlot: plotting genlight objects.

- glPca: PCA for genlight objects.

Examples

## Not run: 
## no structure
x <- glSim(100, 1e3, ploid=2)
plot(x)

## 1,000 non structured SNPs, 100 structured SNPs
x <- glSim(100, 1e3, n.snp.struc=100, ploid=2)
plot(x)

## 1,000 non structured SNPs, 100 structured SNPs, ploidy=4
x <- glSim(100, 1e3, n.snp.struc=100, ploid=4)
plot(x)

## same thing, stronger differences between groups
x <- glSim(100, 1e3, n.snp.struc=100, ploid=2, alpha=0.4)
plot(x)

##  same thing, loci with LD structures
x <- glSim(100, 1e3, n.snp.struc=100, ploid=2, alpha=0.4, LD=TRUE, block.minsize=100)
plot(x)

## End(Not run)

Seasonal influenza (H3N2) HA segment data

Description

The dataset H3N2 consists of 1903 strains of seasonal influenza (H3N2) distributed worldwide, and typed at 125 SNPs located in the hemagglutinin (HA) segment. It is stored as an R object with class genind and can be accessed as usual using data(H3N2) (see example). These data were gathered from DNA sequences available from Genbank (http://www.ncbi.nlm.nih.gov/Genbank/).

Format

H3N2 is a genind object with several data frame as supplementary components (H3N2@other) slort, which contains the following items:

x

a data.frame containing miscellaneous annotations of the sequences.

xy

a matrix with two columns indicating the geographic coordinates of the strains, as longitudes and latitudes.

epid

a character vector indicating the epidemic of the strains.

Details

The data file usflu.fasta is a toy dataset also gathered from Genbank, consisting of the aligned sequences of 80 seasonal influenza isolates (HA segment) sampled in the US, in fasta format. This file is installed alongside the package; the path to this file is automatically determined by R using system.file (see example in this manpage and in ?fasta2genlight) as well.

Source

This dataset was prepared by Thibaut Jombart ([email protected]), from annotated sequences available on Genbank (http://www.ncbi.nlm.nih.gov/Genbank/).

References

Jombart, T., Devillard, S. and Balloux, F. Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. Submitted to BMC genetics.

Examples

## Not run: 
#### H3N2 ####
## LOAD DATA
data(H3N2)
H3N2

## set population to yearly epidemics
pop(H3N2) <- factor(H3N2$other$epid)



## PERFORM DAPC - USE POPULATIONS AS CLUSTERS
## to reproduce exactly analyses from the paper, use "n.pca=1000"
dapc1 <- dapc(H3N2, all.contrib=TRUE, scale=FALSE, n.pca=150, n.da=5)
dapc1

## (see ?dapc for details about the output)


## SCREEPLOT OF EIGENVALUES
barplot(dapc1$eig, main="H3N2 - DAPC eigenvalues")


## SCATTERPLOT (axes 1-2)
scatter(dapc1, posi.da="topleft", cstar=FALSE, cex=2, pch=17:22,
solid=.5, bg="white")




#### usflu.fasta ####
myPath <- system.file("files/usflu.fasta",package="adegenet")
myPath

## extract SNPs from alignments using fasta2genlight
## see ?fasta2genlight for more details
obj <- fasta2genlight(myPath, chunk=10) # process 10 sequences at a time
obj

## End(Not run)

Simulation of genealogies of haplotypes

Description

The function haploGen implements simulations of genealogies of haplotypes. This forward-time, individual-based simulation tool allows haplotypes to replicate and mutate according to specified parameters, and keeps track of their genealogy.

Simulations can be spatially explicit or not (see geo.sim argument). In the first case, haplotypes are assigned to locations on a regular grip. New haplotypes disperse from their ancestor's location according to a random Poisson diffusion, or alternatively according to a pre-specified migration scheme. This tool does not allow for simulating selection or linkage disequilibrium.

Produced objects are lists with the class haploGen; see 'value' section for more information on this class. Other functions are available to print, plot, subset, sample or convert haploGen objects. A seqTrack method is also provided for analysing haploGen objects.

Note that for simulation of outbreaks, the new tool simOutbreak in the outbreaker package should be used.

Usage

haploGen(seq.length=1e4, mu.transi=1e-4, mu.transv=mu.transi/2, t.max=20,
         gen.time=function(){1+rpois(1,0.5)},
         repro=function(){rpois(1,1.5)}, max.nb.haplo=200,
         geo.sim=FALSE, grid.size=10, lambda.xy=0.5,
         mat.connect=NULL,
         ini.n=1, ini.xy=NULL)
## S3 method for class 'haploGen'
print(x, ...)
## S3 method for class 'haploGen'
as.igraph(x, col.pal=redpal, ...)
## S3 method for class 'haploGen'
plot(x, y=NULL, col.pal=redpal, ...)
## S3 method for class 'haploGen'
x[i, j, drop=FALSE]
## S3 method for class 'haploGen'
labels(object, ...)
## S3 method for class 'haploGen'
as.POSIXct(x, tz="", origin=as.POSIXct("2000/01/01"), ...)
## S3 method for class 'haploGen'
seqTrack(x, best=c("min","max"), prox.mat=NULL, ...)
as.seqTrack.haploGen(x)
plotHaploGen(x, annot=FALSE, date.range=NULL, col=NULL, bg="grey", add=FALSE, ...)
sample.haploGen(x, n)

Arguments

seq.length

an integer indicating the length of the simulated haplotypes, in number of nucleotides.

mu.transi

the rate of transitions, in number of mutation per site and per time unit.

mu.transv

the rate of transversions, in number of mutation per site and per time unit.

t.max

an integer indicating the maximum number of time units to run the simulation for.

gen.time

an integer indicating the generation time, in number of time units. Can be a (fixed) number or a function returning a number (then called for each reproduction event).

repro

an integer indicating the number of descendents per haplotype. Can be a (fixed) number or a function returning a number (then called for each reproduction event).

max.nb.haplo

an integer indicating the maximum number of haplotypes handled at any time of the simulation, used to control the size of the produced object. Larger number will lead to slower simulations. If this number is exceeded, the genealogy is prunded to as to keep this number of haplotypes.

geo.sim

a logical stating whether simulations should be spatially explicit (TRUE) or not (FALSE, default). Spatially-explicit simulations are slightly slower than their non-spatial counterpart.

grid.size

the size of the square grid of possible locations for spatial simulations. The total number of locations will be this number squared.

lambda.xy

the parameter of the Poisson distribution used to determine dispersion in x and y axes.

mat.connect

a matrix of connectivity describing migration amongts all pairs of locations. mat.connect[i,j] indicates the probability, being in 'i', to migrate to 'j'. The rows of this matrix thus sum to 1. It has as many rows and columns as there are locations, with row 'i' / column 'j' corresponding to locations number 'i' and 'j'. Locations are numbered as in a matrix in which rows and columns are respectively x and y coordinates. For instance, in a 5x5 grid, locations are numbered as in matrix(1:25,5,5).

ini.n

an integer specifying the number of (identical) haplotypes to initiate the simulation

ini.xy

a vector of two integers giving the x/y coordinates of the initial haplotype.

x, object

haploGen objects.

y

unused argument, for compatibility with 'plot'.

col.pal

a color palette to be used to represent weights using colors on the edges of the graph. See ?num2col. Note that the palette is inversed by default.

i, j, drop

i is a vector used for subsetting the object. For instance, i=1:3 will retain only the first three haplotypes of the genealogy. j and drop are only provided for compatibility, but not used.

best, prox.mat

arguments to be passed to the seqTrack function. See documentation of seqTrack for more information.

annot, date.range, col, bg, add

arguments to be passed to plotSeqTrack.

n

an integer indicating the number of haplotypes to be retained in the sample

tz, origin

aguments to be passed to as.POSIXct (see ?as.POSIXct)

...

further arguments to be passed to other methods; for 'plot', arguments are passed to plot.igraph.

Details

=== Dependencies with other packages ===
- ape package is required as it implements efficient handling of DNA sequences used in haploGen objects. To install this package, simply type:
install.packages("ape")

- for various purposes including plotting, converting genealogies to graphs can be useful. From adegenet version 1.3-5 onwards, this is achieved using the package igraph. See below.

=== Converting haploGen objects to graphs ===
haploGen objects can be converted to igraph objects (package igraph), which can in turn be plotted and manipulated using classical graph tools. Simply use 'as.igraph(x)' where 'x' is a haploGen object. This functionality requires the igraph package. Graphs are time oriented (top=old, bottom=recent).

Value

=== haploGen class ===
haploGen objects are lists containing the following slots:
- seq: DNA sequences in the DNAbin matrix format
- dates: dates of appearance of the haplotypes
- ances: a vector of integers giving the index of each haplotype's ancestor
- id: a vector of integers giving the index of each haplotype
- xy: (optional) a matrix of spatial coordinates of haplotypes
- call: the matched call

=== misc functions ===
- as.POSIXct: returns a vector of dates with POSIXct format
- labels: returns the labels of the haplotypes
- as.seqTrack: returns a seqTrack object. Note that this object is not a proper seqTrack analysis, but just a format conversion convenient for plotting haploGen objects.

Author(s)

Thibaut Jombart [email protected]

References

Jombart T, Eggo R, Dodd P, Balloux F (2010) Reconstructing disease outbreaks from genetic data: a graph approach. Heredity. doi: 10.1038/hdy.2010.78.

See Also

simOutbreak in the package 'outbreaker' for simulating disease outbreaks under a realistic epidemiological model.

Examples

## Not run: 
if(require(ape) && require(igraph)){
## PERFORM SIMULATIONS
x <- haploGen(geo.sim=TRUE)
x

## PLOT DATA
plot(x)

## PLOT SPATIAL SPREAD
plotHaploGen(x, bg="white")
title("Spatial dispersion")


## USE SEQTRACK RECONSTRUCTION
x.recons <- seqTrack(x)
mean(x.recons$ances==x$ances, na.rm=TRUE) # proportion of correct reconstructions

g <- as.igraph(x)
g
plot(g)
plot(g, vertex.size=0)


}

## End(Not run)

Access and manipulate the population hierarchy for genind or genlight objects.

Description

The following methods allow the user to quickly change the hierarchy or population of a genind or genlight object.

Usage

hier(x, formula = NULL, combine = TRUE, value)

hier(x) <- value

Arguments

x

a genind or genlight object

formula

a nested formula indicating the order of the population hierarchy to be returned.

combine

if TRUE (default), the levels will be combined according to the formula argument. If it is FALSE, the levels will not be combined.

value

a formula specifying the full hierarchy of columns in the strata slot. (See Details below)

Details

You must first specify your strata before you can specify your hierarchies. Hierarchies are special cases of strata in that the levels must be nested within each other. An error will occur if you specify a hierarchy that is not truly hierarchical.

Details on Formulas

The preferred use of these functions is with a formula object. Specifically, a hierarchical formula argument is used to name which strata are hierarchical. An example of a hierarchical formula would be:

~Country/City/Neighborhood

This convention was chosen as it becomes easier to type and makes intuitive sense when defining a hierarchy. Note: it is important to use hierarchical formulas when specifying hierarchies as other types of formulas (eg. ~Country*City*Neighborhood) will give incorrect results.

Author(s)

Zhian N. Kamvar

See Also

strata genind as.genind

Examples

# let's look at the microbov data set:
data(microbov)
microbov

# We see that we have three vectors of different names in the 'other' slot. 
?microbov
# These are Country, Breed, and Species
names(other(microbov))

# Let's set the hierarchy
strata(microbov) <- data.frame(other(microbov))
microbov

# And change the names so we know what they are
nameStrata(microbov) <- ~Country/Breed/Species

# let's see what the hierarchy looks like by Species and Breed:
hier(microbov) <- ~Species/Breed
head(hier(microbov, ~Species/Breed))

Expected heterozygosity (Hs)

Description

This function computes the expected heterozygosity (Hs) within populations of a genpop object. This function is available for codominant markers (@type="codom") only. Hs is commonly used for measuring within population genetic diversity (and as such, it still has sense when computed from haploid data).

Usage

Hs(x, pop = NULL)

Arguments

x

a genind or genpop object.

pop

only used if x is a genind; an optional factor to be used as population; if not provided, pop(x) is used.

Details

Let m(k) be the number of alleles of locus k, with a total of K loci. We note fif_i the allele frequency of allele i in a given population. Then, HsHs is given for a given population by:

1Kk=1K(1i=1m(k)fi2)\frac{1}{K} \sum_{k=1}^K (1 - \sum_{i=1}^{m(k)} f_i^2)

Value

a vector of Hs values (one value per population)

Author(s)

Thibaut Jombart [email protected]

See Also

Hs.test to test differences in Hs between two groups

Examples

## Not run: 
data(nancycats)
Hs(genind2genpop(nancycats))

## End(Not run)

Test differences in expected heterozygosity (Hs)

Description

This procedure permits to test if two groups have significant differences in expected heterozygosity (Hs). The test statistic used is simply the difference in Hs between the two groups 'x' and 'y':

Usage

Hs.test(x, y, n.sim = 999, alter = c("two-sided", "greater", "less"))

Arguments

x

a genind object.

y

a genind object.

n.sim

the number of permutations to be used to generate the reference distribution.

alter

a character string indicating the alternative hypothesis

Details

Hs(x)Hs(y)Hs(x) - Hs(y)

Individuals are randomly permuted between groups to obtain a reference distribution of the test statistics.

Value

an object of the class randtest

Author(s)

Thibaut Jombart [email protected]

See Also

Hs to compute Hs for different populations; as.randtest for the class of Monte Carlo tests.

Examples

## Not run: 
data(microbov)
Hs(microbov)
test <- Hs.test(microbov[pop="Borgou"],
                microbov[pop="Lagunaire"],
                n.sim=499)
test
plot(test)

## End(Not run)

Hardy-Weinberg Equilibrium test for multilocus data

Description

The function HWE.test is a generic function to perform Hardy-Weinberg Equilibrium tests defined by the genetics package. adegenet proposes a method for genind objects.

The output can be of two forms:
- a list of tests (class htest) for each locus-population combinaison
- a population x locus matrix containing p-values of the tests

Usage

## S3 method for class 'genind'
HWE.test(x,pop=NULL,permut=FALSE,nsim=1999,hide.NA=TRUE,res.type=c("full","matrix"))

Arguments

x

an object of class genind.

pop

a factor giving the population of each individual. If NULL, pop is seeked from x$pop.

permut

a logical passed to HWE.test stating whether Monte Carlo version (TRUE) should be used or not (FALSE, default).

nsim

number of simulations if Monte Carlo is used (passed to HWE.test).

hide.NA

a logical stating whether non-tested loci (e.g., when an allele is fixed) should be hidden in the results (TRUE, default) or not (FALSE).

res.type

a character or a character vector whose only first argument is considered giving the type of result to display. If "full", then a list of complete tests is returned. If "matrix", then a matrix of p-values is returned.

Details

Monte Carlo procedure is quiet computer-intensive when large datasets are involved. For more precision on the performed test, read HWE.test documentation (genetics package).

Value

Returns either a list of tests or a matrix of p-values. In the first case, each test is designated by locus first and then by population. For instance if res is the "full" output of the function, then the test for population "PopA" at locus "Myloc" is given by res$Myloc$PopA. If res is a matrix of p-values, populations are in rows and loci in columns. P-values are given for the upper-tail: they correspond to the probability that an oberved chi-square statistic as high as or higher than the one observed occured under H0 (HWE).

In all cases, NA values are likely to appear in fixed loci, or entirely non-typed loci.

Author(s)

Thibaut Jombart [email protected]

See Also

HWE.test in the genetics package, chisq.test

Examples

## Not run: 
data(nancycats)
obj <- nancycats
if(require(genetics)){
obj.test <- HWE.test(obj)

# pvalues matrix to have a preview
HWE.test(obj,res.type="matrix")

#more precise view to...
obj.test$fca90$P10
}

## End(Not run)

Function hybridize takes two genind in inputs and generates hybrids individuals having one parent in both objects.

Description

The function hybridize performs hybridization between two set of genotypes stored in genind objects (referred as the "2 populations"). Allelic frequencies are derived for each population, and then gametes are sampled following a multinomial distribution.

Usage

hybridize(
  x1,
  x2,
  n,
  pop = "hybrid",
  res.type = c("genind", "df", "STRUCTURE"),
  file = NULL,
  quiet = FALSE,
  sep = "/",
  hyb.label = "h"
)

Arguments

x1

a genind object

x2

a genind object

n

an integer giving the number of hybrids requested

pop

a character string giving naming the population of the created hybrids.

res.type

a character giving the type of output requested. Must be "genind" (default), "df" (i.e. data.frame like in genind2df), or "STRUCTURE" to generate a .str file readable by STRUCTURE (in which case the 'file' must be supplied). See 'details' for STRUCTURE output.

file

a character giving the name of the file to be written when 'res.type' is "STRUCTURE"; if NULL, a the created file is of the form "hybrids_[the current date].str".

quiet

a logical specifying whether the writing to a file (when 'res.type' is "STRUCTURE") should be announced (FALSE, default) or not (TRUE).

sep

a character used to separate two alleles

hyb.label

a character string used to construct the hybrids labels; by default, "h", which gives labels: "h01", "h02", "h03",...

Details

The result consists in a set of 'n' genotypes, with different possible outputs (see 'res.type' argument).

If the output is a STRUCTURE file, this file will have the following caracteristics:
- file contains the genotypes of the parents, and then the genotypes of hybrids
- the first column identifies genotypes
- the second column identifies the population (1 and 2 for parents x1 and x2; 3 for hybrids)
- the first line contains the names of the markers
- one row = one genotype (onerowperind will be true)
- missing values coded by "-9" (the software's default)

Value

A genind object (by default), or a data.frame of alleles (res.type="df"). No R output if res.type="STRUCTURE" (results written to the specified file).

Author(s)

Thibaut Jombart [email protected]

See Also

seploc, seppop, repool

Examples

## Not run: 
## Let's make some cattle hybrids
data(microbov)

## first, isolate each breed
temp <- seppop(microbov)
names(temp)
salers <- temp$Salers
zebu <- temp$Zebu

## let's make some... Zeblers
zebler <- hybridize(salers, zebu, n=40,
                    pop="Zebler")


## now let's merge all data into a single genind
newDat <- repool(microbov, zebler)

## make a correspondance analysis
## and see where hybrids are placed
X <- genind2genpop(newDat, quiet=TRUE)
coa1 <- dudi.coa(tab(X),scannf=FALSE,nf=3)
s.label(coa1$li)
add.scatter.eig(coa1$eig,2,1,2)


## End(Not run)

Toy hybrid dataset

Description

Toy hybrid dataset

Format

a genind object

Author(s)

Data simulated by Marie-Pauline Beugin. Example by Thibaut Jombart.

Examples

data(hybridtoy)
x <- hybridtoy
pca1 <- dudi.pca(tab(x), scannf=FALSE, scale=FALSE)
s.class(pca1$li, pop(x))

if(require(ggplot2)) {
p <- ggplot(pca1$li, aes(x=Axis1)) +
    geom_density(aes(fill=pop(x)), alpha=.4, adjust=1) +
    geom_point(aes(y=0, color=pop(x)), pch="|", size=10, alpha=.5)
p
}

## kmeans
km <- find.clusters(x, n.pca=10, n.clust=2)
table(pop(x), km$grp)

## dapc
dapc1 <- dapc(x, pop=km$grp, n.pca=10, n.da=1)
scatter(dapc1)
scatter(dapc1, grp=pop(x))
compoplot(dapc1, col.pal=spectral, n.col=2)

## ML-EM with hybrids
res <- snapclust(x, k=2, hybrids=TRUE, detailed=TRUE)
compoplot(res, n.col=3)
table(res$group, pop(x))

Importing data from several softwares to a genind object

Description

Their are several ways to import genotype data to a genind object: i) from a data.frame with a given format (see df2genind), ii) from a file with a recognized extension, or iii) from an alignement of sequences (see DNAbin2genind).

Usage

import2genind(file, quiet = FALSE, ...)

Arguments

file

a character string giving the path to the file to convert, with the appropriate extension.

quiet

logical stating whether a conversion message must be printed (TRUE,default) or not (FALSE).

...

other arguments passed to the appropriate 'read' function (currently passed to read.structure)

Details

The function import2genind detects the extension of the file given in argument and seeks for an appropriate import function to create a genind object.
Current recognized formats are :
- GENETIX files (.gtx)
- Genepop files (.gen)
- Fstat files (.dat)
- STRUCTURE files (.str or .stru)

Beware: same data in different formats are not expected to produce exactly the same genind objects.
For instance, conversions made by GENETIX to Fstat may change the the sorting of the genotypes; GENETIX stores individual names whereas Fstat does not; Genepop chooses a sample's name from the name of its last genotype; etc.

Value

an object of the class genind

Author(s)

Thibaut Jombart [email protected]

References

Belkhir K., Borsa P., Chikhi L., Raufaste N. & Bonhomme F. (1996-2004) GENETIX 4.05, logiciel sous Windows TM pour la genetique des populations. Laboratoire Genome, Populations, Interactions, CNRS UMR 5000, Universite de Montpellier II, Montpellier (France).

Pritchard, J.; Stephens, M. & Donnelly, P. (2000) Inference of population structure using multilocus genotype data. Genetics, 155: 945-959

Raymond M. & Rousset F, (1995). GENEPOP (version 1.2): population genetics software for exact tests and ecumenicism. J. Heredity, 86:248-249

Fstat (version 2.9.3). Software by Jerome Goudet. http://www2.unil.ch/popgen/softwares/fstat.htm

Excoffier L. & Heckel G.(2006) Computer programs for population genetics data analysis: a survival guide Nature, 7: 745-758

See Also

import2genind, read.genetix, read.fstat, read.structure, read.genepop

Examples

import2genind(system.file("files/nancycats.gtx",
package="adegenet"))

import2genind(system.file("files/nancycats.dat",
package="adegenet"))

import2genind(system.file("files/nancycats.gen",
package="adegenet"))

import2genind(system.file("files/nancycats.str",
package="adegenet"), onerowperind=FALSE, n.ind=237, n.loc=9, col.lab=1, col.pop=2, ask=FALSE)

Likelihood-based estimation of inbreeding

Description

The function inbreeding estimates the inbreeding coefficient of an individuals (F) by computing its likelihood function. It can return either the density of probability of F, or a sample of F values from this distribution. This operation is performed for all the individuals of a genind object. Any ploidy greater than 1 is acceptable.

Usage

inbreeding(x, pop = NULL, truenames = TRUE, 
           res.type = c("sample", "function", "estimate"), N = 200, M = N * 10)

Arguments

x

an object of class genind.

pop

a factor giving the 'population' of each individual. If NULL, pop is seeked from pop(x). Note that the term population refers in fact to any grouping of individuals'.

truenames

a logical indicating whether true names should be used (TRUE, default) instead of generic labels (FALSE); used if res.type is "matrix".

res.type

a character string matching "sample", "function", or "estimate" specifying whether the output should be a function giving the density of probability of F values ("function"), the maximum likelihood estimate of F from this distribution ("estimate"), or a sample of F values taken from this distribution ("sample", default).

N

an integer indicating the size of the sample to be taken from the distribution of F values.

M

an integer indicating the number of different F values to be used to generate the sample. Values larger than N are recommended to avoid poor sampling of the distribution.

Details

Let FF denote the inbreeding coefficient, defined as the probability for an individual to inherit two identical alleles from a single ancestor.

Let pip_i refer to the frequency of allele ii in the population. Let hh be an variable which equates 1 if the individual is homozygote, and 0 otherwise. For one locus, the probability of being homozygote is computed as:

F+(1F)ipi2F + (1-F) \sum_i p_i^2

The probability of being heterozygote is: 1(F+(1F)ipi2)1 - (F + (1-F) \sum_i p_i^2)

The likelihood of a genotype is defined as the probability of being the observed state (homozygote or heterozygote). In the case of multilocus genotypes, log-likelihood are summed over the loci.

Value

A named list with one component for each individual, each of which is a function or a vector of sampled F values (see res.type argument).

Author(s)

Thibaut Jombart [email protected]
Zhian N. Kamvar

See Also

Hs: computation of expected heterozygosity.

Examples

## Not run: 
## cattle breed microsatellite data
data(microbov)

## isolate Lagunaire breed
lagun <- seppop(microbov)$Lagunaire

## estimate inbreeding - return sample of F values
Fsamp <- inbreeding(lagun, N=30)

## plot the first 10 results
invisible(sapply(Fsamp[1:10], function(e) plot(density(e), xlab="F",
xlim=c(0,1), main="Density of the sampled F values")))

## compute means for all individuals
Fmean=sapply(Fsamp, mean)
hist(Fmean, col="orange", xlab="mean value of F",
main="Distribution of mean F across individuals")

## estimate inbreeding - return proba density functions
Fdens <- inbreeding(lagun, res.type="function")

## view function for the first individual
Fdens[[1]]

## plot the first 10 functions
invisible(sapply(Fdens[1:10], plot, ylab="Density",
main="Density of probability of F values"))

## estimate inbreeding - return maximum likelihood estimates
Fest <- inbreeding(lagun, res.type = "estimate")
mostInbred <- which.max(Fest)
plot(Fdens[[mostInbred]], ylab = "Density", xlab = "F",
     main = paste("Probability density of F values\nfor", names(mostInbred)))
abline(v = Fest[mostInbred], col = "red", lty = 2)
legend("topright", legend = "MLE", col = "red", lty = 2)

## note that estimates and average samples are likely to be different.
plot(Fest, ylab = "F", col = "blue",
     main = "comparison of MLE and average sample estimates of F")
points(Fmean, pch = 2, col = "red")
arrows(x0 = 1:length(Fest), y0 = Fest, 
       y1 = Fmean, x1 = 1:length(Fest), length = 0.125)
legend("topleft", legend = c("estimate", "sample"), col = c("blue", "red"),
       pch = c(1, 2), title = "res.type")

## End(Not run)

genind constructor

Description

The function new has a method for building genind objects. See the class description of genind for more information on this data structure. The functions genind and as.genind are aliases for new("genind", ...).

Usage

## S4 method for signature 'genind'
initialize(
  .Object,
  tab,
  pop = NULL,
  prevcall = NULL,
  ploidy = 2L,
  type = c("codom", "PA"),
  strata = NULL,
  hierarchy = NULL,
  ...
)

genind(...)

as.genind(...)

Arguments

.Object

prototyped object (generated automatically when calling 'new')

tab

A matrix of integers corresponding to the @tab slot of a genind object, with individuals in rows and alleles in columns, and containing either allele counts (if type="codom") or allele presence/absence (if type="PA")

pop

an optional factor with one value per row in tab indicating the population of each individual

prevcall

an optional call to be stored in the object

ploidy

an integer vector indicating the ploidy of the individual; each individual can have a different value; if only one value is provided, it is recycled to generate a vector of the right length.

type

a character string indicating the type of marker: codominant ("codom") or presence/absence ("PA")

strata

a data frame containing population hierarchies or stratifications in columns. This must be the same length as the number of individuals in the data set.

hierarchy

a hierarchical formula defining the columns of the strata slot that are hierarchical. Defaults to NULL.

...

further arguments passed to other methods (currently not used)

Details

Most users do not need using the constructor, but merely to convert raw allele data using df2genind and related functions.

Value

a genind object

See Also

the description of the genind class; df2genind


genpop constructor

Description

The function new has a method for building genpop objects. See the class description of genpop for more information on this data structure. The functions genpop and as.genpop are aliases for new("genpop", ...).

Usage

## S4 method for signature 'genpop'
initialize(
  .Object,
  tab,
  prevcall = NULL,
  ploidy = 2L,
  type = c("codom", "PA"),
  ...
)

genpop(...)

as.genpop(...)

Arguments

.Object

prototyped object (generated automatically when calling 'new')

tab

A matrix of integers corresponding to the @tab slot of a genpop object, with individuals in rows and alleles in columns, and containing either allele counts

prevcall

an optional call to be stored in the object

ploidy

an integer vector indicating the ploidy of the individual; each individual can have a different value; if only one value is provided, it is recycled to generate a vector of the right length.

type

a character string indicating the type of marker: codominant ("codom") or presence/absence ("PA")

...

further arguments passed to other methods (currently not used)

Details

Most users do not need using the constructor, but merely to convert raw allele data using genind2genpop.

Value

a genpop object

See Also

the description of the genpop class; df2genind and related functions for reading raw allele data


Assess polymorphism in genind/genpop objects

Description

The simple function isPoly can be used to check which loci are polymorphic, or alternatively to check which alleles give rise to polymorphism.

Usage

## S4 method for signature 'genind'
isPoly(x, by=c("locus","allele"), thres=1/100)
## S4 method for signature 'genpop'
isPoly(x, by=c("locus","allele"), thres=1/100)

Arguments

x

a genind and genpop object

by

a character being "locus" or "allele", indicating whether results should indicate polymorphic loci ("locus"), or alleles giving rise to polymorphism ("allele").

thres

a numeric value giving the minimum frequency of an allele giving rise to polymorphism (defaults to 0.01).

Value

A vector of logicals.

Author(s)

Thibaut Jombart [email protected]

Examples

## Not run: 
data(nancycats)
isPoly(nancycats,by="loc", thres=0.1)
isPoly(nancycats[1:3],by="loc", thres=0.1)
genind2df(nancycats[1:3])

## End(Not run)

Compute Akaike Information Criterion for small samples (AICc) for snapclust

Description

Do not use. We work on that stuff. Contact us if interested.

Usage

KIC(object, ...)

## S3 method for class 'snapclust'
KIC(object, ...)

Arguments

object

An object returned by the function snapclust.

...

Further arguments for compatibility with the AIC generic (currently not used).

Author(s)

Thibaut Jombart [email protected]

See Also

snapclust to generate clustering solutions.


Represents a cloud of points with colors

Description

The loadingplot function represents positive values of a vector and identifies the values above a given threshold. It can also indicate groups of observations provided as a factor.

Such graphics can be used, for instance, to assess the weight of each variable (loadings) in a given analysis.

Usage

loadingplot(x, ...)

## Default S3 method:
loadingplot(x, at=NULL, threshold=quantile(x,0.75),
            axis=1, fac=NULL, byfac=FALSE,
            lab=NULL, cex.lab=0.7, cex.fac=1, lab.jitter=0,
            main="Loading plot", xlab="Variables", ylab="Loadings",
            srt = 0, adj = NULL, ...)

Arguments

x

either a vector with numeric values to be plotted, or a matrix-like object containing numeric values. In such case, the x[,axis] is used as vector of values to be plotted.

at

an optional numeric vector giving the abscissa at which loadings are plotted. Useful when variates are SNPs with a known position in an alignement.

threshold

a threshold value above which values of x are identified. By default, this is the third quartile of x.

axis

an integer indicating the column of x to be plotted; used only if x is a matrix-like object.

fac

a factor defining groups of observations.

byfac

a logical stating whether loadings should be averaged by groups of observations, as defined by fac.

lab

a character vector giving the labels used to annotate values above the threshold; if NULL, names are taken from the object.

cex.lab

a numeric value indicating the size of annotations.

cex.fac

a numeric value indicating the size of annotations for groups of observations.

lab.jitter

a numeric value indicating the factor of randomisation for the position of annotations. Set to 0 (by default) implies no randomisation.

main

the main title of the figure.

xlab

the title of the x axis.

ylab

the title of the y axis.

srt

rotation of the labels; see ?text.

adj

adjustment of the labels; see ?text.

...

further arguments to be passed to the plot function.

Value

Invisibly returns a list with the following components:
- threshold: the threshold used
- var.names: the names of observations above the threshold
- var.idx: the indices of observations above the threshold
- var.values: the values above the threshold

Author(s)

Thibaut Jombart [email protected]

Examples

x <- runif(20)
names(x) <- letters[1:20]
grp <- factor(paste("group", rep(1:4,each=5)))

## basic plot
loadingplot(x)

## adding groups
loadingplot(x,fac=grp,main="My title",cex.lab=1)

Compute allelic frequencies

Description

The function makefreq is a generic to compute allele frequencies. These can be derived for genind or genpop objects. In the case of genind objects, data are kept at the individual level, but standardised so that allele frequencies sum up to 1.

Usage

makefreq(x, ...)

## S4 method for signature 'genind'
makefreq(x, quiet = FALSE, missing = NA, truenames = TRUE, ...)

## S4 method for signature 'genpop'
makefreq(x, quiet = FALSE, missing = NA, truenames = TRUE, ...)

Arguments

x

a genind or genpop object.

...

further arguments (curently unused)

quiet

logical stating whether a conversion message must be printed (TRUE,default) or not (FALSE).

missing

treatment for missing values. Can be NA, 0 or "mean" (see details)

truenames

deprecated; there for backward compatibility

Details

There are 3 treatments for missing values:
- NA: kept as NA.
- 0: missing values are considered as zero. Recommended for a PCA on compositionnal data.
- "mean": missing values are given the mean frequency of the corresponding allele. Recommended for a centred PCA.

Note that this function is now a simple wrapper for the accessor tab.

Value

Returns a list with the following components:

tab

matrix of allelic frequencies (rows: populations; columns: alleles).

nobs

number of observations (i.e. alleles) for each population x locus combinaison.

call

the matched call

Author(s)

Thibaut Jombart [email protected]

See Also

genpop

Examples

## Not run: 
data(microbov)
obj1 <- microbov
obj2 <- genind2genpop(obj1)

# perform a correspondance analysis on counts data
Xcount <- tab(obj2, NA.method="zero")
ca1 <- dudi.coa(Xcount,scannf=FALSE)
s.label(ca1$li,sub="Correspondance Analysis",csub=1.2)
add.scatter.eig(ca1$eig,nf=2,xax=1,yax=2,posi="topleft")

# perform a principal component analysis on frequency data
Xfreq <- makefreq(obj2, missing="mean")
Xfreq <- tab(obj2, NA.method="mean") # equivalent to line above
pca1 <- dudi.pca(Xfreq,scale=FALSE,scannf=FALSE)
s.label(pca1$li,sub="Principal Component Analysis",csub=1.2)
add.scatter.eig(pca1$eig,nf=2,xax=1,yax=2,posi="top")

## End(Not run)

Microsatellites genotypes of 15 cattle breeds

Description

This data set gives the genotypes of 704 cattle individuals for 30 microsatellites recommended by the FAO. The individuals are divided into two countries (Afric, France), two species (Bos taurus, Bos indicus) and 15 breeds. Individuals were chosen in order to avoid pseudoreplication according to their exact genealogy.

Format

microbov is a genind object with 3 supplementary components:

coun

a factor giving the country of each individual (AF: Afric; FR: France).

breed

a factor giving the breed of each individual.

spe

is a factor giving the species of each individual (BT: Bos taurus; BI: Bos indicus).

Source

Data prepared by Katayoun Moazami-Goudarzi and Denis Lalo\"e (INRA, Jouy-en-Josas, France)

References

Lalo\"e D., Jombart T., Dufour A.-B. and Moazami-Goudarzi K. (2007) Consensus genetic structuring and typological value of markers using Multiple Co-Inertia Analysis. Genetics Selection Evolution. 39: 545–567.

Examples

## Not run: 
data(microbov)
microbov
summary(microbov)

# make Y, a genpop object
Y <- genind2genpop(microbov)

# make allelic frequency table
temp <- makefreq(Y,missing="mean")
X <- temp$tab
nsamp <- temp$nobs

# perform 1 PCA per marker

kX <- ktab.data.frame(data.frame(X),Y@loc.n.all)

kpca <- list()
for(i in 1:30) {kpca[[i]] <- dudi.pca(kX[[i]],scannf=FALSE,nf=2,center=TRUE,scale=FALSE)}


sel <- sample(1:30,4)
col = rep('red',15)
col[c(2,10)] = 'darkred'
col[c(4,12,14)] = 'deepskyblue4'
col[c(8,15)] = 'darkblue'

# display %PCA
par(mfrow=c(2,2))
for(i in sel) {
s.multinom(kpca[[i]]$c1,kX[[i]],n.sample=nsamp[,i],coulrow=col,sub=locNames(Y)[i])
add.scatter.eig(kpca[[i]]$eig,3,xax=1,yax=2,posi="top")
}

# perform a Multiple Coinertia Analysis
kXcent <- kX
for(i in 1:30) kXcent[[i]] <- as.data.frame(scalewt(kX[[i]],center=TRUE,scale=FALSE))
mcoa1 <- mcoa(kXcent,scannf=FALSE,nf=3, option="uniform")

# coordinated %PCA
mcoa.axes <- split(mcoa1$axis, Y@loc.fac)
mcoa.coord <- split(mcoa1$Tli,mcoa1$TL[,1])
var.coord <- lapply(mcoa.coord,function(e) apply(e,2,var))

par(mfrow=c(2,2))
for(i in sel) {
s.multinom(mcoa.axes[[i]][,1:2],kX[[i]],n.sample=nsamp[,i],coulrow=col,sub=locNames(Y)[i])
add.scatter.eig(var.coord[[i]],2,xax=1,yax=2,posi="top")
}

# reference typology
par(mfrow=c(1,1))
s.label(mcoa1$SynVar,lab=popNames(microbov),sub="Reference typology",csub=1.5)
add.scatter.eig(mcoa1$pseudoeig,nf=3,xax=1,yax=2,posi="top")

# typologial values
tv <- mcoa1$cov2
tv <- apply(tv,2,function(c) c/sum(c))*100
rownames(tv) <- locNames(Y)
tv <- tv[order(locNames(Y)),]

par(mfrow=c(3,1),mar=c(5,3,3,4),las=3)
for(i in 1:3){
barplot(round(tv[,i],3),ylim=c(0,12),yaxt="n",main=paste("Typological value -
structure",i))
axis(side=2,at=seq(0,12,by=2),labels=paste(seq(0,12,by=2),"%"),cex=3)
abline(h=seq(0,12,by=2),col="grey",lty=2)
}

## End(Not run)

Compute minor allele frequency

Description

This function computes the minor allele frequency for each locus in a genind object. To test if loci are polymorphic, see the function isPoly.

Usage

minorAllele(x)

Arguments

x

a genind object

Author(s)

Thibaut Jombart [email protected]

See Also

isPoly

Examples

## Not run: 

## LOAD DATA
data(nancycats)

## COMPUTE ALLELE FREQUENCIES
x <- nancycats
apply(tab(x, freq=TRUE),2,mean, na.rm=TRUE)

## GET MINOR ALLELE FREQUENCY
m.freq <- minorAllele(x)
m.freq

## End(Not run)

Boundary detection using Monmonier algorithm

Description

The Monmonier's algorithm detects boundaries among vertices of a valuated graph. This is achieved by finding the path exhibiting the largest distances between connected vertices.

The highest distance between two connected vertices (i.e. neighbours) is found, giving the starting point of the path. Then, the algorithm seeks the highest distance between immediate neighbours, and so on until a threshold value is attained. This threshold can be chosen from the plot of sorted distances between connected vertices: a boundary will likely result in an abrupt decrease of these values.

When several paths are looked for, the previous paths are taken into account, and cannot be either crossed or redrawn. Monmonier's algorithm can be used to assess the boundaries between patches of homogeneous observations.

Although Monmonier algorithm was initially designed for Voronoi tesselation, this implementation generalizes this algorithm to different connection networks. The optimize.monmonier function produces a monmonier object by trying several starting points, and returning the best boundary (i.e. largest sum of local distances). This is designed to avoid the algorithm to be trapped by a single strong local difference inside an homogeneous patch.

Usage

monmonier(xy, dist, cn, threshold=NULL, bd.length=NULL, nrun=1,
skip.local.diff=rep(0,nrun),scanthres=is.null(threshold), allowLoop=TRUE)

optimize.monmonier(xy, dist, cn, ntry=10, bd.length=NULL, return.best=TRUE,
display.graph=TRUE, threshold=NULL, scanthres=is.null(threshold), allowLoop=TRUE)

## S3 method for class 'monmonier'
plot(x, variable=NULL,
displayed.runs=1:x$nrun, add.arrows=TRUE,
col='blue', lty=1, bwd=4, clegend=1, csize=0.7,
method=c('squaresize','greylevel'), sub='', csub=1, possub='topleft',
cneig=1, pixmap=NULL, contour=NULL, area=NULL, add.plot=FALSE, ...)

## S3 method for class 'monmonier'
print(x, ...)

Arguments

xy

a matrix yielding the spatial coordinates of the objects, with two columns respectively giving X and Y

dist

an object of class dist, giving the distances between the objects

cn

a connection network of class nb (package spdep)

threshold

a number giving the minimal distance between two neighbours crossed by the path; by default, this is the third quartile of all the distances between neighbours

bd.length

an optional integer giving the requested length of the boundaries (in number of local differences)

nrun

is a integer giving the number of runs of the algorithm, that is, the number of paths to search, being one by default

skip.local.diff

is a vector of integers, whose length is the number of paths (nrun); each integer gives the number of starting point to skip, to avoid being stuck in a local difference between two neighbours into an homogeneous patch; none are skipped by default

scanthres

a logical stating whether the threshold sould be chosen from the barplot of sorted distances between neighbours

allowLoop

a logical specifying whether the boundary can loop (TRUE, default) or not (FALSE)

ntry

an integer giving the number of different starting points tried.

return.best

a logical stating whether the best monmonier object should be returned (TRUE, default) or not (FALSE)

display.graph

a logical whether the scores of each try should be plotted (TRUE, default) or not

x

a monmonier object

variable

a variable to be plotted using s.value (package ade4)

displayed.runs

an integer vector giving the rank of the paths to represent

add.arrows

a logical, stating whether arrows should indicate the direction of the path (TRUE) or not (FALSE, used by default)

col

a characters vector giving the colors to be used for each boundary; recycled is needed; 'blue' is used by default

lty

a characters vector giving the type of line to be used for each boundary; 1 is used by default

bwd

a number giving the boundary width factor, applying to every segments of the paths; 4 is used by default

clegend

like in s.value, the size factor of the legend if a variable is represented

csize

like in s.value, the size factor of the squares used to represent a variable

method

like in s.value, a character giving the method to be used to represent the variable, either 'squaresize' (by default) or 'greylevel'

sub

a string of characters giving the subtitle of the plot

csub

the size factor of the subtitle

possub

the position of the subtitle; available choices are 'topleft' (by default), 'topright', 'bottomleft', and 'bottomright'

cneig

the size factor of the connection network

pixmap

an object of the class pixmap displayed in the map background

contour

a data frame with 4 columns to plot the contour of the map: each row gives a segment (x1,y1,x2,y2)

area

a data frame of class 'area' to plot a set of surface units in contour

add.plot

a logical stating whether the plot should be added to the current one (TRUE), or displayed in a new window (FALSE, by default)

...

further arguments passed to other methods

Details

The function monmonier returns a list of the class monmonier, which contains the general informations about the algorithm, and about each run. When displayed, the width of the boundaries reflects their 'strength'. Let a segment MN be part of the path, M being the middle of AB, N of CD. Then the boundary width for MN is proportionnal to (d(AB)+d(CD))/2.

As there is no perfect method to display graphically a quantitative variable (see for instance the differences between the two methods of s.value), the boundaries provided by this algorithm seem sometimes more reliable than the boundaries our eyes perceive (or miss).

Value

Returns an object of class monmonier, which contains the following elements :

run1 (run2, ...)

for each run, a list containing a dataframe giving the path coordinates, and a vector of the distances between neighbours of the path

nrun

the number of runs performed, i.e. the number of boundaries in the monmonier object

threshold

the threshold value, minimal distance between neighbours accounted for by the algorithm

xy

the matrix of spatial coordinates

cn

the connection network of class nb

call

the call of the function

Author(s)

Thibaut Jombart [email protected]

References

Monmonier, M. (1973) Maximum-difference barriers: an alternative numerical regionalization method. Geographic Analysis, 3, 245–261.

Manni, F., Guerard, E. and Heyer, E. (2004) Geographic patterns of (genetic, morphologic, linguistic) variation: how barriers can be detected by "Monmonier's algorithm". Human Biology, 76, 173–190

See Also

spca,edit.nb

Examples

if(require(spdep)){

### non-interactive example

# est-west separation
load(system.file("files/mondata1.rda",package="adegenet"))
cn1 <- chooseCN(mondata1$xy,type=2,ask=FALSE)
mon1 <- monmonier(mondata1$xy,dist(mondata1$x1),cn1,threshold=2)
plot(mon1,mondata1$x1)
plot(mon1,mondata1$x1,met="greylevel",add.arr=FALSE,col="red",bwd=6,lty=2)

# square in the middle
load(system.file("files/mondata2.rda",package="adegenet"))
cn2 <- chooseCN(mondata2$xy,type=1,ask=FALSE)
mon2 <- monmonier(mondata2$xy,dist(mondata2$x2),cn2,threshold=2)
plot(mon2,mondata2$x2,method="greylevel",add.arr=FALSE,bwd=6,col="red",csize=.5)

### genetic data example
## Not run: 
data(sim2pop)

if(require(hierfstat)){
## try and find the Fst
fstat(sim2pop,fst=TRUE)
# Fst = 0.038
}

## run monmonier algorithm

# build connection network
gab <- chooseCN(sim2pop@other$xy,ask=FALSE,type=2)

# filter random noise 
pca1 <- dudi.pca(sim2pop@tab,scale=FALSE, scannf=FALSE, nf=1)

# run the algorithm
mon1 <- monmonier(sim2pop@other$xy,dist(pca1$l1[,1]),gab,scanthres=FALSE)

# graphical display 
plot(mon1,var=pca1$l1[,1])
temp <- sim2pop@pop
levels(temp) <- c(17,19)
temp <- as.numeric(as.character(temp))
plot(mon1)
points(sim2pop@other$xy,pch=temp,cex=2)
legend("topright",leg=c("Pop A", "Pop B"),pch=c(17,19))


### interactive example

# north-south separation
xy <- matrix(runif(120,0,10), ncol=2)
x1 <- rnorm(60)
x1[xy[,2] > 5] <- x1[xy[,2] > 5]+3
cn1 <- chooseCN(xy,type=1,ask=FALSE)
mon1 <- optimize.monmonier(xy,dist(x1)^2,cn1,ntry=10)

# graphics
plot(mon1,x1,met="greylevel",csize=.6)

# island in the middle
x2 <- rnorm(60)
sel <- (xy[,1]>3.5 & xy[,2]>3.5 & xy[,1]<6.5 & xy[,2]<6.5)
x2[sel] <- x2[sel]+4
cn2 <- chooseCN(xy,type=1,ask=FALSE)
mon2 <- optimize.monmonier(xy,dist(x2)^2,cn2,ntry=10)

# graphics
plot(mon2,x2,method="greylevel",add.arr=FALSE,bwd=6,col="red",csize=.5)

## End(Not run)
}

Microsatellites genotypes of 237 cats from 17 colonies of Nancy (France)

Description

This data set gives the genotypes of 237 cats (Felis catus L.) for 9 microsatellites markers. The individuals are divided into 17 colonies whose spatial coordinates are also provided.

Format

nancycats is a genind object with spatial coordinates of the colonies as a supplementary components (@xy).

Source

Dominique Pontier (UMR CNRS 5558, University Lyon1, France)

References

Devillard, S.; Jombart, T. & Pontier, D. Disentangling spatial and genetic structure of stray cat (Felis catus L.) colonies in urban habitat using: not all colonies are equal. submitted to Molecular Ecology

Examples

## Not run: 
data(nancycats)
nancycats

# summary's results are stored in x
x <- summary(nancycats)

# some useful graphics
barplot(x$loc.n.all,ylab="Alleles numbers",main="Alleles numbers
per locus")

plot(x$pop.eff,x$pop.nall,type="n",xlab="Sample size",ylab="Number of alleles")
text(x$pop.eff,y=x$pop.nall,lab=names(x$pop.nall))

par(las=3)
barplot(table(nancycats@pop),ylab="Number of genotypes",main="Number of genotypes per colony")

# are cats structured among colonies ?
if(require(hierfstat)){

gtest <- gstat.randtest(nancycats,nsim=99)
gtest
plot(gtest)


dat <- genind2hierfstat(nancycats)

Fstat <- varcomp.glob(dat$pop,dat[,-1])
Fstat
}

## End(Not run)

Convert objects with obsolete classes into new objects

Description

The genind and genlight objects have changed in Adegenet version 2.0. They have each gained strata and hierarchy slots. What's more is that the genind objects have been optimized for storage and now store the tab slot as integers instead of numerics. This function will convert old genind or genlight objects to new ones seamlessly.

Usage

old2new_genind(object, donor = new("genind"))

old2new_genlight(object, donor = new("genlight"))

old2new_genpop(object, donor = new("genpop"))

Arguments

object

a genind or genlight object from version 1.4 or earlier.

donor

a new object to place all the data into.

Author(s)

Thibaut Jombart [email protected]
Zhian N. Kamvar [email protected]


Pairwise distance plots

Description

The function pairDistPlot extracts and plots pairwise distances between different groups (graphs use ggplot2). The function pairDistPlot does the same, without the graphs.

pairDistPlot is a generic function with methods for the following types of objects:
- dist
- matrix (only numeric data)
- genind objects (genetic markers, individuals)
- DNAbin objects (DNA sequences)

Usage

pairDist(x, ...)

pairDistPlot(x, ...)

## S3 method for class 'dist'
pairDistPlot(x, grp, within=FALSE, sep="-", data=TRUE,
             violin=TRUE, boxplot=TRUE, jitter=TRUE, ...)

## S3 method for class 'matrix'
pairDistPlot(x, grp, within=FALSE, sep="-", data=TRUE,
             violin=TRUE, boxplot=TRUE, jitter=TRUE, ...)

## S3 method for class 'genind'
pairDistPlot(x, grp, within=FALSE, sep="-", data=TRUE,
             violin=TRUE, boxplot=TRUE, jitter=TRUE, ...)

## S3 method for class 'DNAbin'
pairDistPlot(x, grp, within=FALSE, sep="-", data=TRUE,
             violin=TRUE, boxplot=TRUE, jitter=TRUE, ...)

Arguments

x

pairwise distances provided as a dist or a symmetric matrix, or genind or DNAbin object. For genind objects, pairwise squared Euclidean distances are computed from the allele data. For DNAbin objects, distances are computed uing dist.dna, and '...' is used to pass arguments to the function.

grp

a factor defining a grouping of individuals.

within

a logical indicating whether to keep within-group comparisons.

sep

a character used as separator between group names

data

a logical indicating whether data of the plot should be returned.

violin

a logical indicating whether a violinplot should be generated.

boxplot

a logical indicating whether a boxplot should be generated.

jitter

a logical indicating whether a jitter-plot should be generated.

...

further arguments to be used by other functions; used for DNAbin object to pass argumetns to dist.dna.

Value

A list with different components, depending on the values of the arguments. Plots are returned as ggplot2 objects.

Author(s)

Thibaut Jombart [email protected].

See Also

gengraph to identify connectivity based on distances.

Examples

## Not run: 

## use a subset of influenza data
data(H3N2)
set.seed(1)
dat <- H3N2[sample(1:nInd(H3N2), 100)]

## get pairwise distances
temp <- pairDistPlot(dat, other(dat)$epid)

## see raw data
head(temp$data)

## see plots
temp$boxplot
temp$violin
temp$jitter


## End(Not run)

Compute proportion of shared alleles

Description

The function propShared computes the proportion of shared alleles in a set of genotypes (i.e. from a genind object). Current implementation works for any level of ploidy.

Usage

propShared(obj)

Arguments

obj

a genind object.

Details

Computations of the numbers of shared alleles are done in C. Proportions are computed from all available data, i.e. proportion can be computed as far as there is at least one typed locus in common between two genotypes.

Value

Returns a matrix of proportions

Author(s)

Thibaut Jombart [email protected]

See Also

dist.genpop

Examples

## Not run: 
## make a small object
data(microbov)
obj <- microbov[1:5, loc = locNames(microbov)[1:2]]

## verify results
propShared(obj)
genind2df(obj,sep="|")

## Use this similarity measure inside a PCoA
##  ! This is for illustration only !
## the distance should be rendered Euclidean before
## (e.g. using cailliez from package ade4).
matSimil <- propShared(microbov)
matDist <- exp(-matSimil)
D <- cailliez(as.dist(matDist))
pcoa1 <- dudi.pco(D,scannf=FALSE,nf=3)
s.class(pcoa1$li,microbov$pop,lab=popNames(microbov))


## End(Not run)

Compute the proportion of typed elements

Description

The generic function propTyped is devoted to investigating the structure of missing data in adegenet objects.

Methods are defined for genind and genpop objects. They can return the proportion of available (i.e. non-missing) data per individual/population, locus, or the combination of both in with case the matrix indicates which entity (individual or population) was typed on which locus.

Usage

## S4 method for signature 'genind'
propTyped(x,  by=c("ind","loc","both"))
## S4 method for signature 'genpop'
propTyped(x,  by=c("pop","loc","both"))

Arguments

x

a genind and genpop object

by

a character being "ind","loc", or "both" for genind object and "pop","loc", or "both" for genpop object. It specifies whether proportion of typed data are provided by entity ("ind"/"pop"), by locus ("loc") or both ("both"). See details.

Details

When by is set to "both", the result is a matrix of binary data with entities in rows (individuals or populations) and markers in columns. The values of the matrix are 1 for typed data, and 0 for NA.

Value

A vector of proportion (when by equals "ind", "pop", or "loc"), or a matrix of binary data (when by equals "both")

Author(s)

Thibaut Jombart [email protected]

Examples

## Not run: 
data(nancycats)
propTyped(nancycats,by="loc")
propTyped(genind2genpop(nancycats),by="both")

## End(Not run)

Reading data from Fstat

Description

The function read.fstat reads Fstat data files (.dat) and convert them into a genind object.

Usage

read.fstat(file, quiet = FALSE)

Arguments

file

a character string giving the path to the file to convert, with the appropriate extension.

quiet

logical stating whether a conversion message must be printed (TRUE,default) or not (FALSE).

Details

Note: read.fstat is meant for DIPLOID DATA ONLY. Haploid data with the Hierfstat format can be read into R using read.table or read.csv after removing headers and 'POP' lines, and then converted using df2genind.

Value

an object of the class genind

Author(s)

Thibaut Jombart [email protected]

References

Fstat (version 2.9.3). Software by Jerome Goudet. http://www2.unil.ch/popgen/softwares/fstat.htm

See Also

import2genind, df2genind, read.genetix, read.structure, read.genepop

Examples

obj <- read.fstat(system.file("files/nancycats.dat",package="adegenet"))
obj

Reading data from Genepop

Description

The function read.genepop reads Genepop data files (.gen) and convert them into a genind object.

Usage

read.genepop(file, ncode = 2L, quiet = FALSE)

Arguments

file

a character string giving the path to the file to convert, with the appropriate extension.

ncode

an integer indicating the number of characters used to code an allele.

quiet

logical stating whether a conversion message must be printed (TRUE,default) or not (FALSE).

Details

Note: read.genepop is meant for DIPLOID DATA ONLY. Haploid data with the Genepop format can be read into R using read.table or read.csv after removing headers and 'POP' lines, and then converted using df2genind.

Value

an object of the class genind

Author(s)

Thibaut Jombart [email protected]

References

Raymond M. & Rousset F, (1995). GENEPOP (version 1.2): population genetics software for exact tests and ecumenicism. J. Heredity, 86:248-249

See Also

import2genind, df2genind, read.fstat, read.structure, read.genetix

Examples

obj <- read.genepop(system.file("files/nancycats.gen",package="adegenet"))
obj

Reading data from GENETIX

Description

The function read.genetix reads GENETIX data files (.gtx) and convert them into a genind object.

Usage

read.genetix(file = NULL, quiet = FALSE)

Arguments

file

a character string giving the path to the file to convert, with the appropriate extension.

quiet

logical stating whether a conversion message must be printed (TRUE,default) or not (FALSE).

Details

Note: read.genetix is meant for DIPLOID DATA ONLY. Haploid data with the GENETIX format can be read into R using read.table or read.csv after removing headers and 'POP' lines, and then converted using df2genind.

Value

an object of the class genind

Author(s)

Thibaut Jombart [email protected]

References

Belkhir K., Borsa P., Chikhi L., Raufaste N. & Bonhomme F. (1996-2004) GENETIX 4.05, logiciel sous Windows TM pour la genetique des populations. Laboratoire Genome, Populations, Interactions, CNRS UMR 5000, Universite de Montpellier II, Montpellier (France).

See Also

import2genind, df2genind, read.fstat, read.structure, read.genepop

Examples

obj <- read.genetix(system.file("files/nancycats.gtx",package="adegenet"))
obj

Reading Single Nucleotide Polymorphism data

Description

The function read.snp reads a SNP data file with extension '.snp' and converts it into a genlight object. This format is devoted to handle biallelic SNP only, but can accommodate massive datasets such as complete genomes with considerably less memory than other formats.

Usage

read.snp(
  file,
  quiet = FALSE,
  chunkSize = 1000,
  parallel = FALSE,
  n.cores = NULL,
  ...
)

Arguments

file

a character string giving the path to the file to convert, with the extension ".snp".

quiet

logical stating whether a conversion messages should be printed (TRUE,default) or not (FALSE).

chunkSize

an integer indicating the number of genomes to be read at a time; larger values require more RAM but decrease the time needed to read the data.

parallel

a logical indicating whether multiple cores -if available- should be used for the computations (TRUE, default), or not (FALSE); requires the package parallel to be installed (see details).

n.cores

if parallel is TRUE, the number of cores to be used in the computations; if NULL, then the maximum number of cores available on the computer is used.

...

other arguments to be passed to other functions - currently not used.

Details

The function reads data by chunks of a few genomes (minimum 1, no maximum) at a time, which allows one to read massive datasets with negligible RAM requirements (albeit at a cost of computational time). The argument chunkSize indicates the number of genomes read at a time. Increasing this value decreases the computational time required to read data in, while increasing memory requirements.

A description of the .snp format is provided in an example file distributed with adegenet (see example below).

=== The .snp format ===

Details of the .snp format can be found in the example file distributed with adegenet (see below), or on the adegenet website (type adegenetWeb() in R).

Value

an object of the class "genlight"

Author(s)

Thibaut Jombart [email protected]

See Also

- ?genlight for a description of the class "genlight".

- read.PLINK: read SNPs in PLINK's '.raw' format.

- fasta2genlight: extract SNPs from alignments with fasta format.

- df2genind: convert any multiallelic markers into adegenet "genlight".

- import2genind: read multiallelic markers from various software into adegenet.

Examples

## Not run: 
## show the example file ##
## this is the path to the file:
system.file("files/exampleSnpDat.snp",package="adegenet")

## show its content:
file.show(system.file("files/exampleSnpDat.snp",package="adegenet"))


## read the file
obj <-
read.snp(system.file("files/exampleSnpDat.snp",package="adegenet"), chunk=2)
obj
as.matrix(obj)
ploidy(obj)
alleles(obj)
locNames(obj)

## End(Not run)

Reading data from STRUCTURE

Description

The function read.structure reads STRUCTURE data files (.str ou .stru) and convert them into a genind object. By default, this function is interactive and asks a few questions about data content. This can be disabled (for optional questions) by turning the 'ask' argument to FALSE. However, one has to know the number of genotypes, of markers and if genotypes are coded on a single or on two rows before importing data.

Usage

read.structure(
  file,
  n.ind = NULL,
  n.loc = NULL,
  onerowperind = NULL,
  col.lab = NULL,
  col.pop = NULL,
  col.others = NULL,
  row.marknames = NULL,
  NA.char = "-9",
  pop = NULL,
  sep = NULL,
  ask = TRUE,
  quiet = FALSE
)

Arguments

file

a character string giving the path to the file to convert, with the appropriate extension.

n.ind

an integer giving the number of genotypes (or 'individuals') in the dataset

n.loc

an integer giving the number of markers in the dataset

onerowperind

a STRUCTURE coding option: are genotypes coded on a single row (TRUE), or on two rows (FALSE, default)

col.lab

an integer giving the index of the column containing labels of genotypes. '0' if absent.

col.pop

an integer giving the index of the column containing population to which genotypes belong. '0' if absent.

col.others

an vector of integers giving the indexes of the columns containing other informations to be read. Will be available in @other of the created object.

row.marknames

an integer giving the index of the row containing the names of the markers. '0' if absent.

NA.char

the character string coding missing data. "-9" by default. Note that in any case, series of zero (like "000") are interpreted as NA too.

pop

an optional factor giving the population of each individual.

sep

a character string used as separator between alleles.

ask

a logical specifying if the function should ask for optional informations about the dataset (TRUE, default), or try to be as quiet as possible (FALSE).

quiet

logical stating whether a conversion message must be printed (TRUE,default) or not (FALSE).

Details

Note: read.structure is meant for DIPLOID DATA ONLY. Haploid data with the STRUCTURE format can easily be read into R using read.table or read.csv and then converted using df2genind.

Value

an object of the class genind

Author(s)

Thibaut Jombart [email protected]

References

Pritchard, J.; Stephens, M. & Donnelly, P. (2000) Inference of population structure using multilocus genotype data. Genetics, 155: 945-959

See Also

import2genind, df2genind, read.fstat, read.genetix, read.genepop

Examples

obj <- read.structure(system.file("files/nancycats.str",package="adegenet"),
  onerowperind=FALSE, n.ind=237, n.loc=9, col.lab=1, col.pop=2, ask=FALSE)

obj

Pool several genotypes into a single dataset

Description

The function repool allows to merge genotypes from different genind objects into a single 'pool' (i.e. a new genind). The markers have to be the same for all objects to be merged, but there is no constraint on alleles.

Usage

repool(..., list = FALSE)

Arguments

...

a list of genind objects, or a series of genind objects separated by commas

list

a logical indicating whether a list of objects with matched alleles shall be returned (TRUE), or a single genind object (FALSE, default).

Details

This function can be useful, for instance, when hybrids are created using hybridize, to merge hybrids with their parent population for further analyses. Note that repool can also reverse the action of seppop.

Author(s)

Thibaut Jombart [email protected]

See Also

seploc, seppop

Examples

## Not run: 
## use the cattle breeds dataset
data(microbov)
temp <- seppop(microbov)
names(temp)
## hybridize salers and zebu -- nasty cattle
zebler <- hybridize(temp$Salers, temp$Zebu, n=40)
zebler
## now merge zebler with other cattle breeds
nastyCattle <- repool(microbov, zebler)
nastyCattle

## End(Not run)

Microsatellites genotypes of 335 chamois (Rupicapra rupicapra) from the Bauges mountains (France)

Description

This data set contains the genotypes of 335 chamois (Rupicapra rupicapra) from the Bauges mountains, in France. No prior clustering about individuals is known. Each genotype is georeferenced. These data also contain a raster map of elevation of the sampling area.

Format

rupica is a genind object with 3 supplementary components inside the @other slot:

xy

a matrix containing the spatial coordinates of the genotypes.

mnt

a raster map of elevation, with the asc format from the adehabitat package.

showBauges

a function to display the map of elevation with an appropriate legend (use showBauges()).

Source

Daniel Maillard, 'Office National de la Chasse et de la Faune Sauvage' (ONCFS), France.

References

Cassar S (2008) Organisation spatiale de la variabilité génétique et phénotypique a l'échelle du paysage: le cas du chamois et du chevreuil, en milieu de montagne. PhD Thesis. University Claude Bernard - Lyon 1, France.

Cassar S, Jombart T, Loison A, Pontier D, Dufour A-B, Jullien J-M, Chevrier T, Maillard D. Spatial genetic structure of Alpine chamois (Rupicapra rupicapra): a consequence of landscape features and social factors? submitted to Molecular Ecology.

Examples

data(rupica)
rupica


## Not run: 
required_packages <- require(adehabitat) &&
  require(adespatial) &&
  require(spdep)
if (required_packages) {

## see the sampling area
showBauges <- rupica$other$showBauges
showBauges()
points(rupica$other$xy,col="red")

## perform a sPCA
spca1 <- spca(rupica,type=5,d1=0,d2=2300,plot=FALSE,scannf=FALSE,nfposi=2,nfnega=0)
barplot(spca1$eig,col=rep(c("black","grey"),c(2,100)),main="sPCA eigenvalues")
screeplot(spca1,main="sPCA eigenvalues: decomposition")

## data visualization
showBauges(,labcex=1)
s.value(spca1$xy,spca1$ls[,1],add.p=TRUE,csize=.5)
add.scatter.eig(spca1$eig,1,1,1,posi="topleft",sub="Eigenvalues")

showBauges(,labcex=1)
s.value(spca1$xy,spca1$ls[,2],add.p=TRUE,csize=.5)
add.scatter.eig(spca1$eig,2,2,2,posi="topleft",sub="Eigenvalues")

rupica$other$showBauges()
colorplot(spca1$xy,spca1$li,cex=1.5,add.plot=TRUE)

## global and local tests
Gtest <- global.rtest(rupica@tab,spca1$lw,nperm=999)
Gtest
plot(Gtest)
Ltest <- local.rtest(rupica@tab,spca1$lw,nperm=999)
Ltest
plot(Ltest)
}

## End(Not run)

Compute scaled allele frequencies

Description

The generic function scaleGen is an analogue to the scale function, but is designed with further arguments giving scaling options.

Usage

scaleGen(x, ...)

## S4 method for signature 'genind'
scaleGen(
  x,
  center = TRUE,
  scale = TRUE,
  NA.method = c("asis", "mean", "zero"),
  truenames = TRUE
)

## S4 method for signature 'genpop'
scaleGen(
  x,
  center = TRUE,
  scale = TRUE,
  NA.method = c("asis", "mean", "zero"),
  truenames = TRUE
)

Arguments

x

a genind and genpop object

...

further arguments passed to other methods.

center

a logical stating whether alleles frequencies should be centred to mean zero (default to TRUE). Alternatively, a vector of numeric values, one per allele, can be supplied: these values will be substracted from the allele frequencies.

scale

a logical stating whether alleles frequencies should be scaled (default to TRUE). Alternatively, a vector of numeric values, one per allele, can be supplied: these values will be substracted from the allele frequencies.

NA.method

a method to replace NA; asis: leave NAs as is; mean: replace by the mean allele frequencies; zero: replace by zero

truenames

no longer used; kept for backward compatibility

Details

Methods are defined for genind and genpop objects. Both return data.frames of scaled allele frequencies.

Value

A matrix of scaled allele frequencies with genotypes (genind) or populations in (genpop) in rows and alleles in columns.

Author(s)

Thibaut Jombart [email protected]

Examples

## Not run: 
## load data
data(microbov)
obj <- genind2genpop(microbov)

## apply scaling
X1 <- scaleGen(obj)

## compute PCAs with and without scaling
pcaObj <- dudi.pca(obj, scale = FALSE, scannf = FALSE) # pca with no scaling
pcaX1  <- dudi.pca(X1, scale = FALSE, scannf = FALSE, nf = 100) # pca scaled using scaleGen()
pcaX2  <- dudi.pca(obj, scale = TRUE, scannf = FALSE, nf = 100) # pca scaled in-PCA

## get the loadings of alleles for the two scalings
U1 <- pcaObj$c1
U2 <- pcaX1$c1
U3 <- pcaX2$c1

## find an optimal plane to compare loadings
## use a procustean rotation of loadings tables
pro1 <- procuste(U1, U2, nf = 2)
pro2 <- procuste(U2, U3, nf = 2)
pro3 <- procuste(U1, U3, nf = 2)

## graphics
par(mfrow=c(2, 3))
# eigenvalues
barplot(pcaObj$eig, main = "Eigenvalues\n no scaling")
barplot(pcaX1$eig, main = "Eigenvalues\n scaleGen scaling")
barplot(pcaX2$eig, main = "Eigenvalues\n in-PCA scaling")
# differences between loadings of alleles
s.match(pro1$scorX, pro1$scorY, clab = 0,
        sub = "no scaling -> scaling (procustean rotation)")
s.match(pro2$scorX, pro2$scorY, clab = 0,
        sub = "scaling scaleGen -> in-PCA scaling")
s.match(pro3$scorX, pro3$scorY, clab = 0,
        sub = "no scaling -> in-PCA scaling")


## End(Not run)

Select genotypes of well-represented populations

Description

The function selPopSize checks the sample size of each population in a genind object and keeps only genotypes of populations having a given minimum size.

Usage

## S4 method for signature 'genind'
selPopSize(x,pop=NULL,nMin=10)

Arguments

x

a genind object

pop

a vector of characters or a factor giving the population of each genotype in 'x'. If not provided, seeked from x$pop.

nMin

the minimum sample size for a population to be retained. Samples sizes strictly less than nMin will be discarded, those equal to or greater than nMin are kept.

Value

A genind object.

Author(s)

Thibaut Jombart [email protected]

See Also

seploc, repool

Examples

## Not run: 
data(microbov)

table(pop(microbov))
obj <- selPopSize(microbov, n=50)

obj
table(pop(obj))

## End(Not run)

Separate data per locus

Description

The function seploc splits an object (genind, genpop or genlight) by marker. For genind and genpop objects, the method returns a list of objects whose components each correspond to a marker. For genlight objects, the methods returns blocks of SNPs.

Usage

## S4 method for signature 'genind'
seploc(x,truenames=TRUE,res.type=c("genind","matrix"))
## S4 method for signature 'genpop'
seploc(x,truenames=TRUE,res.type=c("genpop","matrix"))
## S4 method for signature 'genlight'
seploc(x, n.block=NULL, block.size=NULL, random=FALSE,
       parallel=FALSE, n.cores=NULL)

Arguments

x

a genind or a genpop object.

truenames

a logical indicating whether true names should be used (TRUE, default) instead of generic labels (FALSE).

res.type

a character indicating the type of returned results, a genind or genpop object (default) or a matrix of data corresponding to the 'tab' slot.

n.block

an integer indicating the number of blocks of SNPs to be returned.

block.size

an integer indicating the size (in number of SNPs) of the blocks to be returned.

random

should blocks be formed of contiguous SNPs, or should they be made or randomly chosen SNPs.

parallel

a logical indicating whether multiple cores -if available- should be used for the computations (TRUE, default), or not (FALSE); requires the package parallel to be installed.

n.cores

if parallel is TRUE, the number of cores to be used in the computations; if NULL, then the maximum number of cores available on the computer is used.

Value

The function seploc returns an list of objects of the same class as the initial object, or a list of matrices similar to x$tab.

Author(s)

Thibaut Jombart [email protected]

See Also

seppop, repool

Examples

## Not run: 
## example on genind objects
data(microbov)

# separate all markers
obj <- seploc(microbov)
names(obj)

obj$INRA5


## example on genlight objects
x <- glSim(100, 1000, 0, ploidy=2) # simulate data
x <- x[,order(glSum(x))] # reorder loci by frequency of 2nd allele
glPlot(x, main="All data") # plot data
foo <- seploc(x, n.block=3) # form 3 blocks
foo
glPlot(foo[[1]], main="1st block") # plot 1st block
glPlot(foo[[2]], main="2nd block") # plot 2nd block
glPlot(foo[[3]], main="3rd block") # plot 3rd block

foo <- seploc(x, block.size=600, random=TRUE) # split data, randomize loci
foo # note the different block sizes
glPlot(foo[[1]])

## End(Not run)

Separate genotypes per population

Description

The function seppop splits a genind or a genlight object by population, returning a list of objects whose components each correspond to a population.

For genind objects, the output can either be a list of genind (default), or a list of matrices corresponding to the @tab slot.

Usage

## S4 method for signature 'genind'
seppop(x,pop=NULL,truenames=TRUE,res.type=c("genind","matrix"),
  drop=FALSE, treatOther=TRUE, keepNA = FALSE, quiet=TRUE)

## S4 method for signature 'genlight'
seppop(x,pop=NULL, treatOther=TRUE, keepNA = FALSE, quiet=TRUE, ...)

Arguments

x

a genind object

pop

a factor giving the population of each genotype in 'x' OR a formula specifying which strata are to be used when converting to a genpop object. If none provided, population factors are sought in x@pop, but if given, the argument prevails on x@pop.

truenames

a logical indicating whether true names should be used (TRUE, default) instead of generic labels (FALSE); used if res.type is "matrix".

res.type

a character indicating the type of returned results, a list of genind object (default) or a matrix of data corresponding to the 'tab' slots.

drop

a logical stating whether alleles that are no longer present in a subset of data should be discarded (TRUE) or kept anyway (FALSE, default).

treatOther

a logical stating whether elements of the @other slot should be treated as well (TRUE), or not (FALSE). See details in accessor documentations (pop).

keepNA

If there are individuals with missing population information, should they be pooled into a separate population (TRUE), or excluded (FALSE, default).

quiet

a logical indicating whether warnings should be issued when trying to subset components of the @other slot (TRUE), or not (FALSE, default).

...

further arguments passed to the genlight constructor.

Value

According to 'res.type': a list of genind object (default) or a matrix of data corresponding to the 'tab' slots.

Author(s)

Thibaut Jombart [email protected]

See Also

seploc, repool

Examples

## Not run: 
data(microbov)
strata(microbov) <- data.frame(other(microbov))

obj <- seppop(microbov)
names(obj)

obj$Salers

### example using strata
obj2 <- seppop(microbov, ~coun/spe)
names(obj2)

obj2$AF_BI

#### example for genlight objects ####
x <- new("genlight", list(a=rep(1,1e3),b=rep(0,1e3),c=rep(1, 1e3)))
x

pop(x) # no population info
pop(x) <- c("pop1","pop2", "pop1") # set population memberships
pop(x)
seppop(x)
as.matrix(seppop(x)$pop1)[,1:20]
as.matrix(seppop(x)$pop2)[,1:20,drop=FALSE]

## End(Not run)

SeqTrack algorithm for reconstructing genealogies

Description

The SeqTrack algorithm [1] aims at reconstructing genealogies of sampled haplotypes or genotypes for which a collection date is available. Contrary to phylogenetic methods which aims at reconstructing hypothetical ancestors for observed sequences, SeqTrack considers that ancestors and descendents are sampled together, and therefore infers ancestry relationships among the sampled sequences.

This approach proved more efficient than phylogenetic approaches for reconstructing transmission trees in densely sampled disease outbreaks [1]. This implementation defines a generic function seqTrack with methods for specific object classes.

Usage

seqTrack(...)

## S3 method for class 'matrix'
seqTrack(x, x.names, x.dates, best = c("min", "max"),
    prox.mat = NULL, mu = NULL, haplo.length = NULL, ...)

## S3 method for class 'seqTrack'
as.igraph(x, col.pal=redpal, ...)

## S3 method for class 'seqTrack'
plot(x, y=NULL, col.pal=redpal, ...)

plotSeqTrack(x, xy, use.arrows=TRUE, annot=TRUE, labels=NULL, col=NULL,
                         bg="grey", add=FALSE, quiet=FALSE,
                         date.range=NULL, jitter.arrows=0, plot=TRUE, ...)

get.likelihood(...)

## S3 method for class 'seqTrack'
get.likelihood(x, mu, haplo.length, ...)

Arguments

x

for seqTrack, a matrix giving weights to pairs of ancestries such that x[i,j] is the weight of 'i ancestor of j'. For plotSeqTrack and get.likelihood. seqTrack, a seqTrack object.

x.names

a character vector giving the labels of the haplotypes/genotypes

x.dates

a vector of collection dates for the sampled haplotypes/genotypes. Dates must have the POSIXct format. See details or ?as.POSIXct for more information.

best

a character string matching 'min' or 'max', indicating whether genealogies should minimize or maximize the sum of weights of ancestries.

prox.mat

an optional matrix of proximities between haplotypes/genotypes used to resolve ties in the choice of ancestors, by picking up the 'closest' ancestor amongst possible ancestors, in the sense of prox.mat. prox.mat[i,j] must indicate a proximity for the relationship 'i ancestor to j'. For instance, if prox.mat contains spatial proximities, then prox.mat[i,j] gives a measure of how easy it is to migrate from location 'i' to 'j'.

mu

(optional) a mutation rate, per site and per day. When 'x' contains numbers of mutations, used to resolve ties using a maximum likelihood approach (requires haplo.length to be provided).

haplo.length

(optional) the length of analysed sequences in number of nucleotides. When 'x' contains numbers of mutations, used to resolve ties using a maximum likelihood approach (requires mu to be provided).

y

unused argument, for compatibility with 'plot'.

col.pal

a color palette to be used to represent weights using colors on the edges of the graph. See ?num2col. Note that the palette is inversed by default.

xy

spatial coordinates of the sampled haplotypes/genotypes.

use.arrows

a logical indicating whether arrows should be used to represented ancestries (pointing from ancestor to descendent, TRUE), or whether segments shall be used (FALSE).

annot

a logical indicating whether arrows or segments representing ancestries should be annotated (TRUE) or not (FALSE).

labels

a character vector containing annotations of the ancestries. If left empty, ancestries are annotated by the descendent.

col

a vector of colors to be used for plotting ancestries.

bg

a color to be used as background.

add

a logical stating whether the plot should be added to current figure (TRUE), or drawn as a new plot (FALSE, default).

quiet

a logical stating whether messages other than errors should be displayed (FALSE, default), or hidden (TRUE).

date.range

a vector of length two with POSIXct format indicating the time window for which ancestries should be displayed.

jitter.arrows

a positive number indicating the amount of noise to be added to coordinates of arrows; useful when several arrows overlap. See jitter.

plot

a logical stating whether a plot should be drawn (TRUE, default), or not (FALSE). In all cases, the function invisibly returns plotting information.

...

further arguments to be passed to other methods

Details

=== Maximum parsimony genealogies ===
Maximum parsimony genealogies can be obtained easily using this implementation of seqTrack. One has to provide in x a matrix of genetic distances. The most straightforward distance is the number of differing nucleotides. See dist.dna in the ape package for a wide range of genetic distances between aligned sequences. The argument best should be set to "min" (its default value), so that the identified genealogy minimizes the total number of mutations. If x contains number of mutations, then mu and haplo.length should also be provided for resolving ties in equally parsimonious ancestors using maximum likelihood.

=== Likelihood of observed genetic differentiation ===
The probability of oberving a given number of mutations between a sequence and its ancestor can be computed using get.likelihood.seqTrack. Note that this is only possible if x contained number of mutations.

=== Plotting/converting seqTrack objects to graphs ===
seqTrack objects are best plotted as graphs. From adegenet_1.3-5 onwards, seqTrack objects can be converted to igraph objects (from the package igraph), which can in turn be plotted and manipulated using classical graph tools. The plot method does this operation automatically, using colors to represent edge weights, and using time-ordering of the data from top (ancient) to bottom (recent).

Value

=== output of seqTrack ===
seqTrack function returns data.frame with the class seqTrack, in which each row is an inferred ancestry described by the following columns: - id: indices identifying haplotypes/genotypes
- ances: index of the inferred ancestor
- weight: weight of the inferred ancestries
- date: date of the haplotype/genotype
- ances.date: date of the ancestor

=== output of plotSeqTrack ===
This graphical function invisibly returns the coordinates of the arrows/segments drawn and their colors, as a data.frame.

Author(s)

Thibaut Jombart [email protected]

References

Jombart T, Eggo R, Dodd P, Balloux F (2010) Reconstructing disease outbreaks from genetic data: a graph approach. Heredity. doi: 10.1038/hdy.2010.78.

See Also

dist.dna in the ape package to compute pairwise genetic distances in aligned sequences.

Examples

## Not run: 
if(require(ape && require(igraph))){
## ANALYSIS OF SIMULATED DATA ##
## SIMULATE A GENEALOGY
dat <- haploGen(seq.l=1e4, repro=function(){sample(1:4,1)}, gen.time=1, t.max=3)
plot(dat, main="Simulated data")

## SEQTRACK ANALYSIS
res <- seqTrack(dat, mu=0.0001, haplo.length=1e4) 
plot(res, main="seqTrack reconstruction")

## PROPORTION OF CORRECT RECONSTRUCTION
mean(dat$ances==res$ances,na.rm=TRUE)


## ANALYSIS OF PANDEMIC A/H1N1 INFLUENZA DATA ##
## note:
## this is for reproduction purpose only
## seqTrack is best kept for the analysis
## of densely sampled outbreaks, which
## is not the case of this dataset.
## 
dat <- read.csv(system.file("files/pdH1N1-data.csv",package="adegenet"))
ha <-  read.dna(system.file("files/pdH1N1-HA.fasta",package="adegenet"), format="fa")
na <- read.dna(system.file("files/pdH1N1-NA.fasta",package="adegenet"), format="fa")


## COMPUTE NUCLEOTIDIC DISTANCES
nbNucl <- ncol(as.matrix(ha)) + ncol(as.matrix(na))
D <- dist.dna(ha,model="raw")*ncol(as.matrix(ha)) +
dist.dna(na,model="raw")*ncol(as.matrix(na))
D <- round(as.matrix(D))


## MATRIX OF SPATIAL CONNECTIVITY
## (to promote local transmissions)
xy <- cbind(dat$lon, dat$lat)
temp <- as.matrix(dist(xy))
M <- 1* (temp < 1e-10)


## SEQTRACK ANALYSIS
dat$date <- as.POSIXct(dat$date)
res <- seqTrack(D, rownames(dat), dat$date, prox.mat=M, mu=.00502/365, haplo.le=nbNucl)


## COMPUTE GENETIC LIKELIHOOD
p <- get.likelihood(res, mu=.00502/365, haplo.length=nbNucl)
# (these could be shown as colors when plotting results)
# (but mutations will be used instead)


## EXAMINE RESULTS
head(res)
tail(res)
range(res$weight, na.rm=TRUE)
barplot(table(res$weight)/sum(!is.na(res$weight)), ylab="Frequency",
xlab="Mutations between inferred ancestor and descendent", col="orange")


## DISPLAY SPATIO-TEMPORAL DYNAMICS 
if(require(maps)){
myDates <- as.integer(difftime(dat$date, as.POSIXct("2009-01-21"), unit="day"))
myMonth <- as.POSIXct(
c("2009-02-01", "2009-03-01","2009-04-01","2009-05-01","2009-06-01","2009-07-01"))
x.month <-  as.integer(difftime(myMonth, as.POSIXct("2009-01-21"), unit="day"))


## FIRST STAGE:
## SPREAD TO THE USA AND CANADA
curRange <- as.POSIXct(c("2009-03-29","2009-04-25"))
par(bg="deepskyblue")
map("world", fill=TRUE, col="grey")
opal <- palette()
palette(rev(heat.colors(10)))
plotSeqTrack(res, round(xy), add=TRUE,annot=FALSE,lwd=2,date.range=curRange,
col=res$weight+1)
title(paste(curRange, collapse=" to "))
legend("bottom", lty=1, leg=0:8, title="number of mutations", col=1:9,
lwd=2, horiz=TRUE)


## SECOND STAGE:
## SPREAD WITHIN AMERICA, FIRST SEEDING OUTSIDE AMERICA
curRange <- as.POSIXct(c("2009-04-30","2009-05-07"))
par(bg="deepskyblue")
map("world", fill=TRUE, col="grey")
opal <- palette()
palette(rev(heat.colors(10)))
plotSeqTrack(res, round(xy), add=TRUE,annot=FALSE,lwd=2,
date.range=curRange, col=res$weight+1)
title(paste(curRange, collapse=" to "))
legend("bottom", lty=1, leg=0:8, title="number of mutations",
col=1:9,lwd=2, horiz=TRUE)


## THIRD STAGE:
## PANDEMIC
curRange <- as.POSIXct(c("2009-05-15","2009-05-25"))
par(bg="deepskyblue")
map("world", fill=TRUE, col="grey")
opal <- palette()
palette(rev(heat.colors(10)))
plotSeqTrack(res, round(xy), add=TRUE,annot=FALSE,lwd=2, date.range=curRange,
col=res$weight+1)
title(paste(curRange, collapse=" to "))
legend("bottom", lty=1, leg=0:8, title="number of mutations",
col=1:9,lwd=2, horiz=TRUE)

}
}

## End(Not run)

Importing data from an alignement of sequences to a genind object

Description

These functions take an alignement of sequences and translate SNPs into a genind object. Note that only polymorphic loci are retained.

Currently, accepted sequence formats are:
- DNAbin (ape package): function DNAbin2genind
- alignment (seqinr package): function alignment2genind

Usage

DNAbin2genind(x, pop=NULL, exp.char=c("a","t","g","c"), polyThres=1/100)

alignment2genind(x, pop=NULL, exp.char=c("a","t","g","c"), na.char="-",
                 polyThres=1/100)

Arguments

x

an object containing aligned sequences.

pop

an optional factor giving the population to which each sequence belongs.

exp.char

a vector of single character providing expected values; all other characters will be turned to NA.

na.char

a vector of single characters providing values that should be considered as NA. If not NULL, this is used instead of exp.char.

polyThres

the minimum frequency of a minor allele for a locus to be considered as polymorphic (defaults to 0.01).

Value

an object of the class genind

Author(s)

Thibaut Jombart [email protected]

See Also

import2genind, read.genetix, read.fstat, read.structure, read.genepop, DNAbin, as.alignment.

Examples

## Not run: 
data(woodmouse)
x <- DNAbin2genind(woodmouse)
x
genind2df(x)

## End(Not run)

if(require(seqinr)){
mase.res   <- read.alignment(file=system.file("sequences/test.mase",package="seqinr"),
format = "mase")
mase.res
x <- alignment2genind(mase.res)
x
locNames(x) # list of polymorphic sites
genind2df(x)

## look at Euclidean distances
D <- dist(tab(x))
D

## summarise with a PCoA
pco1 <- dudi.pco(D, scannf=FALSE,nf=2)
scatter(pco1, posi="bottomright")
title("Principal Coordinate Analysis\n-based on proteic distances-")

}

Manipulate the population factor of genind objects.

Description

The following methods allow the user to quickly change the population of a genind object.

Usage

setPop(x, formula = NULL)

setPop(x) <- value

Arguments

x

a genind or genlight object

formula

a nested formula indicating the order of the population strata.

value

same as formula

Author(s)

Zhian N. Kamvar

Examples

data(microbov)

strata(microbov) <- data.frame(other(microbov))

# Currently set on just 
head(pop(microbov)) 

# setting the strata to both Pop and Subpop
setPop(microbov) <- ~coun/breed 
head(pop(microbov))

## Not run: 

# Can be used to create objects as well.
microbov.old <- setPop(microbov, ~spe) 
head(pop(microbov.old))

## End(Not run)

When you need a break...

Description

Genetic data analysis can be a harsh, tiring, daunting task. Sometimes, a mere break will not cut it. Sometimes, you need a kitten.

Usage

showmekittens(x = NULL, list = FALSE)

Arguments

x

the name or index of the video to display; if NULL, a random video is chosen

list

a logical indicating if the list of available videos should be displayed

Details

Please send us more! Either pull request or submit an issue with a URL (use adegenetIssues()).

Author(s)

Thibaut Jombart [email protected]


Simulated genotypes of two georeferenced populations

Description

This simple data set was obtained by sampling two populations evolving in a island model, simulated using Easypop (2.0.1). See source for simulation details. Sample sizes were respectively 100 and 30 genotypes. The genotypes were given spatial coordinates so that both populations were spatially differentiated.

Format

sim2pop is a genind object with a matrix of xy coordinates as supplementary component.

Author(s)

Thibaut Jombart [email protected]

Source

Easypop version 2.0.1 was run with the following parameters:
- two diploid populations, one sex, random mating
- 1000 individuals per population
- proportion of migration: 0.002
- 20 loci
- mutation rate: 0.0001 (KAM model)
- maximum of 50 allelic states
- 1000 generations (last one taken)

References

Balloux F (2001) Easypop (version 1.7): a computer program for oppulation genetics simulations Journal of Heredity, 92: 301-302

Examples

## Not run: 
data(sim2pop)

if(require(hierfstat)){
## try and find the Fst
temp <- genind2hierfstat(sim2pop)
varcomp.glob(temp[,1],temp[,-1])
# Fst = 0.038
}

## run monmonier algorithm

# build connection network
gab <- chooseCN(sim2pop@other$xy,ask=FALSE,type=2)

# filter random noise
pca1 <- dudi.pca(sim2pop@tab,scale=FALSE, scannf=FALSE, nf=1)

# run the algorithm
mon1 <- monmonier(sim2pop@other$xy,dist(pca1$l1[,1]),gab, scanthres=FALSE)

# graphical display
temp <- sim2pop@pop
levels(temp) <- c(17,19)
temp <- as.numeric(as.character(temp))
plot(mon1)
points(sim2pop@other$xy,pch=temp,cex=2)
legend("topright",leg=c("Pop A", "Pop B"),pch=c(17,19))

## End(Not run)

Maximum-likelihood genetic clustering using EM algorithm

Description

This function implements the fast maximum-likelihood genetic clustering approach described in Beugin et al (2018). The underlying model is very close to the model implemented by STRUCTURE, but allows for much faster estimation of genetic clusters thanks to the use of the Expectation-Maximization (EM) algorithm. Optionally, the model can explicitely account for hybridization and detect different types of hybrids (see hybrids and hybrid.coef arguments). The method is fully documented in a dedicated tutorial which can be accessed using adegenetTutorial("snapclust").

Usage

snapclust(
  x,
  k,
  pop.ini = "ward",
  max.iter = 100,
  n.start = 10,
  n.start.kmeans = 50,
  hybrids = FALSE,
  dim.ini = 100,
  hybrid.coef = NULL,
  parent.lab = c("A", "B"),
  ...
)

Arguments

x

a genind object

k

the number of clusters to look for

pop.ini

parameter indicating how the initial group membership should be found. If NULL, groups are chosen at random, and the algorithm will be run n.start times. If "kmeans", then the function find.clusters is used to define initial groups using the K-means algorithm. If "ward", then the function find.clusters is used to define initial groups using the Ward algorithm. Alternatively, a factor defining the initial cluster configuration can be provided.

max.iter

the maximum number of iteration of the EM algorithm

n.start

the number of times the EM algorithm is run, each time with different random starting conditions

n.start.kmeans

the number of times the K-means algorithm is run to define the starting point of the ML-EM algorithm, each time with different random starting conditions

hybrids

a logical indicating if hybrids should be modelled explicitely; this is currently implemented for 2 groups only.

dim.ini

the number of PCA axes to retain in the dimension reduction step for find.clusters, if this method is used to define initial group memberships (see argument pop.ini).

hybrid.coef

a vector of hybridization coefficients, defining the proportion of hybrid gene pool coming from the first parental population; this is symmetrized around 0.5, so that e.g. c(0.25, 0.5) will be converted to c(0.25, 0.5, 0.75)

parent.lab

a vector of 2 character strings used to label the two parental populations; only used if hybrids are detected (see argument hybrids)

...

further arguments passed on to find.clusters

Details

The method is described in Beugin et al (2018) A fast likelihood solution to the genetic clustering problem. Methods in Ecology and Evolution doi:10.1111/2041-210X.12968. A dedicated tutorial is available by typing adegenetTutorial("snapclust").

Value

The function snapclust returns a list with the following components:

  • $group a factor indicating the maximum-likelihood assignment of individuals to groups; if identified, hybrids are labelled after hybridization coefficients, e.g. 0.5_A - 0.5_B for F1, 0.75_A - 0.25_B for backcross F1 / A, etc.

  • $ll: the log-likelihood of the model

  • $proba: a matrix of group membership probabilities, with individuals in rows and groups in columns; each value correspond to the probability that a given individual genotype was generated under a given group, under Hardy-Weinberg hypotheses.

  • $converged a logical indicating if the algorithm converged; if FALSE, it is doubtful that the result is an actual Maximum Likelihood estimate.

  • $n.iter an integer indicating the number of iterations the EM algorithm was run for.

Author(s)

Thibaut Jombart [email protected] and Marie-Pauline Beugin

See Also

The function snapclust.choose.k to investigate the optimal value number of clusters 'k'.

Examples

## Not run: 
data(microbov)

## try function using k-means initialization
grp.ini <- find.clusters(microbov, n.clust=15, n.pca=150)

## run EM algo
res <- snapclust(microbov, 15, pop.ini = grp.ini$grp)
names(res)
res$converged
res$n.iter

## plot result
compoplot(res)

## flag potential hybrids
to.flag <- apply(res$proba,1,max)<.9
compoplot(res, subset=to.flag, show.lab=TRUE,
                 posi="bottomleft", bg="white")


## Simulate hybrids F1
zebu <- microbov[pop="Zebu"]
salers <- microbov[pop="Salers"]
hyb <- hybridize(zebu, salers, n=30)
x <- repool(zebu, salers, hyb)

## method without hybrids
res.no.hyb <- snapclust(x, k=2, hybrids=FALSE)
compoplot(res.no.hyb, col.pal=spectral, n.col=2)

## method with hybrids
res.hyb <- snapclust(x, k=2, hybrids=TRUE)
compoplot(res.hyb, col.pal =
          hybridpal(col.pal = spectral), n.col = 2)


## Simulate hybrids backcross (F1 / parental)
f1.zebu <- hybridize(hyb, zebu, 20, pop = "f1.zebu")
f1.salers <- hybridize(hyb, salers, 25, pop = "f1.salers")
y <- repool(x, f1.zebu, f1.salers)

## method without hybrids
res2.no.hyb <- snapclust(y, k = 2, hybrids = FALSE)
compoplot(res2.no.hyb, col.pal = hybridpal(), n.col = 2)

## method with hybrids F1 only
res2.hyb <- snapclust(y, k = 2, hybrids = TRUE)
compoplot(res2.hyb, col.pal = hybridpal(), n.col = 2)

## method with back-cross
res2.back <- snapclust(y, k = 2, hybrids = TRUE, hybrid.coef = c(.25,.5))
compoplot(res2.back, col.pal = hybridpal(), n.col = 2)


## End(Not run)

Choose the number of clusters for snapclust using AIC, BIC or AICc

Description

This function implements methods for investigating the optimal number of genetic clusters ('k') using the fast maximum-likelihood genetic clustering approach described in Beugin et al (2018). The method runs snapclust for varying values of 'k', and computes the requested summary statistics for each clustering solution to assess goodness of fit. The method is fully documented in a dedicated tutorial which can be accessed using adegenetTutorial("snapclust").

Usage

snapclust.choose.k(max, ..., IC = AIC, IC.only = TRUE)

Arguments

max

An integer indicating the maximum number of clusters to seek; snapclust will be run for all k from 2 to max.

...

Arguments passed to snapclust.

IC

A function computing the information criterion for snapclust objects. Available statistics are AIC (default), AICc, and BIC.

IC.only

A logical (TRUE by default) indicating if IC values only should be returned; if FALSE, full snapclust objects are returned.

Details

The method is described in Beugin et al (2018) A fast likelihood solution to the genetic clustering problem. Methods in Ecology and Evolution doi:10.1111/2041-210X.12968. A dedicated tutorial is available by typing adegenetTutorial("snapclust").

Author(s)

Thibaut Jombart [email protected]

See Also

snapclust to generate individual clustering solutions, and BIC.snapclust for computing BIC for snapclust objects.


Formal class "SNPbin"

Description

The class SNPbin is a formal (S4) class for storing a genotype of binary SNPs in a compact way, using a bit-level coding scheme. This storage is most efficient with haploid data, where the memory taken to represent data can reduced more than 50 times. However, SNPbin can be used for any level of ploidy, and still remain an efficient storage mode.

A SNPbin object can be constructed from a vector of integers giving the number of the second allele for each locus.

SNPbin stores a single genotype. To store multiple genotypes, use the genlight class.

Objects from the class SNPbin

SNPbin objects can be created by calls to new("SNPbin", ...), where '...' can be the following arguments:

snp

a vector of integers or numeric giving numbers of copies of the second alleles for each locus. If only one unnamed argument is provided to 'new', it is considered as this one.

ploidy

an integer indicating the ploidy of the genotype; if not provided, will be guessed from the data (as the maximum from the 'snp' input vector).

label

an optional character string serving as a label for the genotype.

Slots

The following slots are the content of instances of the class SNPbin; note that in most cases, it is better to retrieve information via accessors (see below), rather than by accessing the slots manually.

snp:

a list of vectors with the class raw.

n.loc:

an integer indicating the number of SNPs of the genotype.

NA.posi:

a vector of integer giving the position of missing data.

label:

an optional character string serving as a label for the genotype..

ploidy:

an integer indicating the ploidy of the genotype.

Methods

Here is a list of methods available for SNPbin objects. Most of these methods are accessors, that is, functions which are used to retrieve the content of the object. Specific manpages can exist for accessors with more than one argument. These are indicated by a '*' symbol next to the method's name. This list also contains methods for conversion from SNPbin to other classes.

[

signature(x = "SNPbin"): usual method to subset objects in R. The argument indicates how SNPs are to be subsetted. It can be a vector of signed integers or of logicals.

show

signature(x = "SNPbin"): printing of the object.

$

signature(x = "SNPbin"): similar to the @ operator; used to access the content of slots of the object.

$<-

signature(x = "SNPbin"): similar to the @ operator; used to replace the content of slots of the object.

nLoc

signature(x = "SNPbin"): returns the number of SNPs in the object.

names

signature(x = "SNPbin"): returns the names of the slots of the object.

ploidy

signature(x = "SNPbin"): returns the ploidy of the genotype.

as.integer

signature(x = "SNPbin"): converts a SNPbin object to a vector of integers. The S4 method 'as' can be used as well (e.g. as(x, "integer")).

cbind

signature(x = "SNPbin"): merges genotyping of the same individual at different SNPs (all stored as SNPbin objects) into a single SNPbin.

c

signature(x = "SNPbin"): same as cbind.SNPbin.

Author(s)

Thibaut Jombart ([email protected])

See Also

Related class:
- genlight, for storing multiple binary SNP genotypes.
- genind, for storing other types of genetic markers.

Examples

## Not run: 
#### HAPLOID EXAMPLE ####
## create a genotype of 100,000 SNPs
dat <- sample(c(0,1,NA), 1e5, prob=c(.495, .495, .01), replace=TRUE)
dat[1:10]
x <- new("SNPbin", dat)
x
x[1:10] # subsetting
as.integer(x[1:10])

## try a few accessors
ploidy(x)
nLoc(x)
head(x$snp[[1]]) # internal bit-level coding

## check that conversion is OK
identical(as(x, "integer"),as.integer(dat)) # SHOULD BE TRUE

## compare the size of the objects
print(object.size(dat), unit="auto")
print(object.size(x), unit="auto")
object.size(dat)/object.size(x) # EFFICIENCY OF CONVERSION


#### TETRAPLOID EXAMPLE ####
## create a genotype of 100,000 SNPs
dat <- sample(c(0:4,NA), 1e5, prob=c(rep(.995/5,5), 0.005), replace=TRUE)
x <- new("SNPbin", dat)
identical(as(x, "integer"),as.integer(dat)) # MUST BE TRUE

## compare the size of the objects
print(object.size(dat), unit="auto")
print(object.size(x), unit="auto")
object.size(dat)/object.size(x) # EFFICIENCY OF CONVERSION


#### c, cbind ####
a <- new("SNPbin", c(1,1,1,1,1))
b <- new("SNPbin", c(0,0,0,0,0))
a
b
ab <- c(a,b)
ab
identical(c(a,b),cbind(a,b))
as.integer(ab)

## End(Not run)

Analyse the position of polymorphic sites

Description

These functions are used to describe the distribution of polymorphic sites (SNPs) in an alignment.

The function snpposi.plot plots the positions and density of SNPs in the alignment.

The function snpposi.test tests whether SNPs are randomly distributed in the genome, the alternative hypothesis being that they are clustered. This test is based on the distances of each SNP to the closest SNP. This provides one measure of clustering for each SNP. Different statistics can be used to summarise these values (argument stat), but by default the statistics used is the median.

snpposi.plot and snpposi.test are generic functions with methods for vectors of integers or numeric (indicating SNP position), and for DNAbin objects.

Usage

snpposi.plot(...)

## S3 method for class 'integer'
snpposi.plot(x, genome.size, smooth=0.1,
              col="royalblue", alpha=.2, codon=TRUE, start.at=1, ...)

## S3 method for class 'numeric'
snpposi.plot(x, ...)

## S3 method for class 'DNAbin'
snpposi.plot(x, ...)


snpposi.test(...)

## S3 method for class 'integer'
snpposi.test(x, genome.size, n.sim=999, stat=median, ...)

## S3 method for class 'numeric'
snpposi.test(x, ...)

## S3 method for class 'DNAbin'
snpposi.test(x, ...)

Arguments

x

a vector of integers or numerics containing SNP positions, or a set of aligned sequences in a DNAbin object.

genome.size

an integer indicating the length of genomes.

smooth

a smoothing parameter for the density estimation; smaller values will give more local peaks; values have to be positive but can be less than 1.

col

the color to be used for the plot; ignored if codon positions are represented.

alpha

the alpha level to be used for transparency (density curve).

codon

a logical indicating if codon position should be indicated (TRUE, default) or not.

start.at

an integer indicating at which base of a codon the alignment starts (defaults to 1); values other than 1, 2 and 3 will be ignored.

n.sim

an integer indicating the number of randomizations to be used in the Monte Carlo test.

stat

a function used to summarize the measure of physical proximity between SNPs; by default, the median is used.

...

further arguments to be passed to the integer method.

Value

A Monte Carlo test of the class randtest.

Author(s)

Thibaut Jombart [email protected].

See Also

The fasta2DNAbin to read fasta alignments with minimum RAM use.

Examples

if(require(ape)){
data(woodmouse)
snpposi.plot(woodmouse, codon=FALSE)
snpposi.plot(woodmouse)

## Not run: 
snpposi.test(c(1,3,4,5), 100)
snpposi.test(woodmouse)

## End(Not run)
}

Identification of structural SNPs

Description

The function snpzip identifies the set of alleles which contribute most significantly to phenotypic structure.

This procedure uses Discriminant Analysis of Principal Components (DAPC) to quantify the contribution of individual alleles to between-population structure. Then, defining contribution to DAPC as the measure of distance between alleles, hierarchical clustering is used to identify two groups of alleles: structural SNPs and non-structural SNPs.

Usage

snpzip(snps, y, plot = TRUE, xval.plot = FALSE, loading.plot = FALSE,
         method = c("complete", "single", "average", "centroid", 
                    "mcquitty", "median", "ward"), ...)

Arguments

snps

a snps matrix used as input of DAPC.

y

either a factor indicating the group membership of individuals, or a dapc object.

plot

a logical indicating whether a graphical representation of the DAPC results should be displayed.

xval.plot

a logical indicating whether the results of the cross-validation step should be displayed (iff y is a factor).

loading.plot

a logical indicating whether a loading.plot displaying the SNP selection threshold should be displayed.

method

the clustering method to be used. This should be (an unambiguous abbreviation of) one of "complete", "single", "average", "centroid", "mcquitty", "median", or "ward".

...

further arguments.

Details

snpzip provides an objective procedure to delineate between structural and non-structural SNPs identified by Discriminant Analysis of Principal Components (DAPC, Jombart et al. 2010). snpzip precedes the multivariate analysis with a cross-validation step to ensure that the subsequent DAPC is performed optimally. The contributions of alleles to the DAPC are then submitted to hclust, where they define a distance matrix upon which hierarchical clustering is carried out. To complete the procedure, snpzip uses cutree to automatically subdivide the set of SNPs fed into the analysis into two groups: those which contribute significantly to the phenotypic structure of interest, and those which do not.

Value

A list with four items if y is a factor, or two items if y is a dapc object: The first cites the number of principal components (PCs) of PCA retained in the DAPC.

The second item is an embedded list which first indicates the number of structural and non-structural SNPs identified by snpzip, second provides a list of the structuring alleles, third gives the names of the selected alleles, and fourth details the contributions of these structuring alleles to the DAPC.

The optional third item provides measures of discrimination success both overall and by group.

The optional fourth item contains the dapc object generated if y was a factor.

If plot=TRUE, a scatter plot will provide a visualization of the DAPC results.

If xval.plot=TRUE, the results of the cross-validation step will be displayed as an array of the format generated by xvalDapc, and a scatter plot of the results of cross-validation will be provided.

If loading.plot=TRUE, a loading plot will be generated to show the contributions of alleles to the DAPC, and the SNP selection threshold will be indicated. If the number of Discriminant Axes (n.da) in the DAPC is greater than 1, loading.plot=TRUE will generate one loading plot for each discriminant axis.

Author(s)

Caitlin Collins [email protected]

References

Jombart T, Devillard S and Balloux F (2010) Discriminant analysis of principal components: a new method for the analysis of genetically structured populations. BMC Genetics11:94. doi:10.1186/1471-2156-11-94

Examples

## Not run: 
    simpop <- glSim(100, 10000, n.snp.struc = 10, grp.size = c(0.3,0.7), 
                    LD = FALSE, alpha = 0.4, k = 4)
    snps <- as.matrix(simpop)
    phen <- simpop@pop
    
    outcome <- snpzip(snps, phen, method = "centroid")
    outcome
  
## End(Not run)
  ## Not run: 
    simpop <- glSim(100, 10000, n.snp.struc = 10, grp.size = c(0.3,0.7), 
                    LD = FALSE, alpha = 0.4, k = 4)
    snps <- as.matrix(simpop)
    phen <- simpop@pop
    
    dapc1 <- dapc(snps, phen, n.da = 1, n.pca = 30)
    
    features <- snpzip(dapc1, loading.plot = TRUE, method = "average")
    features
  
## End(Not run)

Spatial principal component analysis

Description

These functions implement the spatial principal component analysis (sPCA). The function spca is a generic with methods for:

  • matrix: only numeric values are accepted

  • data.frame: same as for matrices

  • genind: any genind object is accepted

  • genpop: any genpop object is accepted

The core computation use multispati from the ade4 package.

Besides the set of spca functions, other functions include:

  • print.spca: prints the spca content

  • summary.spca: gives variance and autocorrelation statistics

  • plot.spca: usefull graphics (connection network, 3 different representations of map of scores, eigenvalues barplot and decomposition)

  • screeplot.spca: decomposes spca eigenvalues into variance and autocorrelation

  • colorplot.spca: represents principal components of sPCA in space using the RGB system.

A tutorial on sPCA can be opened using:
adegenetTutorial(which="spca").

Usage

spca(...)

## Default S3 method:
spca(x, ...)

## S3 method for class 'matrix'
spca(x, xy = NULL, cn = NULL, matWeight = NULL,
            center = TRUE, scale = FALSE, scannf = TRUE,
            nfposi = 1, nfnega = 1,
            type = NULL, ask = TRUE,
            plot.nb = TRUE, edit.nb = FALSE,
            truenames = TRUE,
            d1 = NULL, d2 = NULL, k = NULL,
            a = NULL, dmin = NULL, ...)

## S3 method for class 'data.frame'
spca(x, xy = NULL, cn = NULL, matWeight = NULL,
            center = TRUE, scale = FALSE, scannf = TRUE,
            nfposi = 1, nfnega = 1,
            type = NULL, ask = TRUE,
            plot.nb = TRUE, edit.nb = FALSE,
            truenames = TRUE,
            d1 = NULL, d2 = NULL, k = NULL,
            a = NULL, dmin = NULL, ...)

## S3 method for class 'genind'
spca(obj, xy = NULL, cn = NULL, matWeight = NULL,
            scale = FALSE, scannf = TRUE,
            nfposi = 1, nfnega = 1,
            type = NULL, ask = TRUE,
            plot.nb = TRUE, edit.nb = FALSE,
            truenames = TRUE,
            d1 = NULL, d2 = NULL, k = NULL,
            a = NULL, dmin = NULL, ...)

## S3 method for class 'genpop'
spca(obj, xy = NULL, cn = NULL, matWeight = NULL,
            scale = FALSE, scannf = TRUE,
            nfposi = 1, nfnega = 1,
            type = NULL, ask = TRUE,
            plot.nb = TRUE, edit.nb = FALSE,
            truenames = TRUE,
            d1 = NULL, d2 = NULL, k = NULL,
            a = NULL, dmin = NULL, ...)


## S3 method for class 'spca'
print(x, ...)

## S3 method for class 'spca'
summary(object, ..., printres=TRUE)

## S3 method for class 'spca'
plot(x, axis = 1, useLag=FALSE, ...)

## S3 method for class 'spca'
screeplot(x, ..., main=NULL)

## S3 method for class 'spca'
colorplot(x, axes=1:ncol(x$li), useLag=FALSE, ...)

Arguments

x

a matrix or a data.frame of numeric values, with individuals in rows and variables in columns; categorical variables with a binary coding are acceptable too; for print and plotting functions, a spca object.

obj

a genind or genpop object.

xy

a matrix or data.frame with two columns for x and y coordinates. Seeked from obj$other$xy if it exists when xy is not provided. Can be NULL if a nb object is provided in cn.
Longitude/latitude coordinates should be converted first by a given projection (see 'See Also' section).

cn

a connection network of the class 'nb' (package spdep). Can be NULL if xy is provided. Can be easily obtained using the function chooseCN (see details).

matWeight

a square matrix of spatial weights, indicating the spatial proximities between entities. If provided, this argument prevails over cn (see details).

center

a logical indicating whether data should be centred to a mean of zero; used implicitely for genind or genpop objects.

scale

a logical indicating whether data should be scaled to unit variance (TRUE) or not (FALSE, default).

scannf

a logical stating whether eigenvalues should be chosen interactively (TRUE, default) or not (FALSE).

nfposi

an integer giving the number of positive eigenvalues retained ('global structures').

nfnega

an integer giving the number of negative eigenvalues retained ('local structures').

type

an integer giving the type of graph (see details in chooseCN help page). If provided, ask is set to FALSE.

ask

a logical stating whether graph should be chosen interactively (TRUE,default) or not (FALSE).

plot.nb

a logical stating whether the resulting graph should be plotted (TRUE, default) or not (FALSE).

edit.nb

a logical stating whether the resulting graph should be edited manually for corrections (TRUE) or not (FALSE, default).

truenames

a logical stating whether true names should be used for 'obj' (TRUE, default) instead of generic labels (FALSE)

d1

the minimum distance between any two neighbours. Used if type=5.

d2

the maximum distance between any two neighbours. Used if type=5.

k

the number of neighbours per point. Used if type=6.

a

the exponent of the inverse distance matrix. Used if type=7.

dmin

the minimum distance between any two distinct points. Used to avoid infinite spatial proximities (defined as the inversed spatial distances). Used if type=7.

object

a spca object.

printres

a logical stating whether results should be printed on the screen (TRUE, default) or not (FALSE).

axis

an integer between 1 and (nfposi+nfnega) indicating which axis should be plotted.

main

a title for the screeplot; if NULL, a default one is used.

...

further arguments passed to other methods.

axes

the index of the columns of X to be represented. Up to three axes can be chosen.

useLag

a logical stating whether the lagged components (x$ls) should be used instead of the components (x$li).

Details

The spatial principal component analysis (sPCA) is designed to investigate spatial patterns in the genetic variability. Given multilocus genotypes (individual level) or allelic frequency (population level) and spatial coordinates, it finds individuals (or population) scores maximizing the product of variance and spatial autocorrelation (Moran's I). Large positive and negative eigenvalues correspond to global and local structures.

Spatial weights can be obtained in several ways, depending how the arguments xy, cn, and matWeight are set.
When several acceptable ways are used at the same time, priority is as follows:
matWeight > cn > xy

Value

The class spca are given to lists with the following components:

eig

a numeric vector of eigenvalues.

nfposi

an integer giving the number of global structures retained.

nfnega

an integer giving the number of local structures retained.

c1

a data.frame of alleles loadings for each axis.

li

a data.frame of row (individuals or populations) coordinates onto the sPCA axes.

ls

a data.frame of lag vectors of the row coordinates; useful to clarify maps of global scores .

as

a data.frame giving the coordinates of the PCA axes onto the sPCA axes.

call

the matched call.

xy

a matrix of spatial coordinates.

lw

a list of spatial weights of class listw.

Other functions have different outputs:
- summary.spca returns a list with 3 components: Istat giving the null, minimum and maximum Moran's I values; pca gives variance and I statistics for the principal component analysis; spca gives variance and I statistics for the sPCA.

- plot.spca returns the matched call.

- screeplot.spca returns the matched call.

Author(s)

Thibaut Jombart [email protected]

References

Jombart, T., Devillard, S., Dufour, A.-B. and Pontier, D. Revealing cryptic spatial patterns in genetic variability by a new multivariate method. Heredity, 101, 92–103.

Wartenberg, D. E. (1985) Multivariate spatial correlation: a method for exploratory geographical analysis. Geographical Analysis, 17, 263–283.

Moran, P.A.P. (1948) The interpretation of statistical maps. Journal of the Royal Statistical Society, B 10, 243–251.

Moran, P.A.P. (1950) Notes on continuous stochastic phenomena. Biometrika, 37, 17–23.

de Jong, P. and Sprenger, C. and van Veen, F. (1984) On extreme values of Moran's I and Geary's c. Geographical Analysis, 16, 17–24.

See Also

spcaIllus and rupica for datasets illustrating the sPCA
global.rtest and local.rtest
chooseCN, multispati, multispati.randtest
convUL, from the package 'PBSmapping' to convert longitude/latitude to UTM coordinates.

Examples

## data(spcaIllus) illustrates the sPCA
## see ?spcaIllus
##
## Not run: 
example(spcaIllus)
example(rupica)

## End(Not run)

Monte Carlo test for sPCA

Description

The function spca_randtest implements Monte-Carlo tests for the presence of significant spatial structures in a sPCA object. Two tests are run, for global (positive autocorrelation) and local (negative autocorrelation) structures, respectively. The test statistics used are the sum of the absolute values of the corresponding eigenvalues.

Usage

spca_randtest(x, nperm = 499)

Arguments

x

A spca object.

nperm

The number of permutations to be used for the test.

Value

A list with two objects of the class 'randtest' (see as.randtest), the first one for 'global' structures (positivie autocorrelation) and the second for 'local' structures (negative autocorrelation).

Author(s)

Original code by Valeria Montano adapted by Thibaut Jombart.

Examples

## Not run: 
## Load data
data(sim2pop)

## Make spca
spca1 <- spca(sim2pop, type = 1, scannf = FALSE, plot.nb = FALSE)

spca1
plot(spca1)

## run tests (use more permutations in practice, e.g. 999)
tests <- spca_randtest(spca1, nperm = 49)

## check results
tests
plot(tests[[1]]) # global structures


## End(Not run)

Simulated data illustrating the sPCA

Description

Datasets illustrating the spatial Principal Component Analysis (Jombart et al. 2009). These data were simulated using various models using Easypop (2.0.1). Spatial coordinates were defined so that different spatial patterns existed in the data. The spca-illus is a list containing the following genind or genpop objects:
- dat2A: 2 patches
- dat2B: cline between two pop
- dat2C: repulsion among individuals from the same gene pool
- dat3: cline and repulsion
- dat4: patches and local alternance

Format

spcaIllus is list of 5 components being either genind or genpop objects.

Details

See "source" for a reference providing simulation details.

Author(s)

Thibaut Jombart [email protected]

Source

Jombart, T., Devillard, S., Dufour, A.-B. and Pontier, D. Revealing cryptic spatial patterns in genetic variability by a new multivariate method. Heredity, 101, 92–103.

References

Jombart, T., Devillard, S., Dufour, A.-B. and Pontier, D. Revealing cryptic spatial patterns in genetic variability by a new multivariate method. Heredity, 101, 92–103.

Balloux F (2001) Easypop (version 1.7): a computer program for oppulation genetics simulations Journal of Heredity, 92: 301-302

See Also

spca

Examples

required_packages <- require(adespatial) && require(spdep)
if (required_packages) {
data(spcaIllus)
attach(spcaIllus)
opar <- par(no.readonly=TRUE)
## comparison PCA vs sPCA

# PCA
pca2A <- dudi.pca(dat2A$tab,center=TRUE,scale=FALSE,scannf=FALSE)
pca2B <- dudi.pca(dat2B$tab,center=TRUE,scale=FALSE,scannf=FALSE)
pca2C <- dudi.pca(dat2C$tab,center=TRUE,scale=FALSE,scannf=FALSE)
pca3 <- dudi.pca(dat3$tab,center=TRUE,scale=FALSE,scannf=FALSE,nf=2)
pca4 <- dudi.pca(dat4$tab,center=TRUE,scale=FALSE,scannf=FALSE,nf=2)

# sPCA
spca2A <-spca(dat2A,xy=dat2A$other$xy,ask=FALSE,type=1,
plot=FALSE,scannf=FALSE,nfposi=1,nfnega=0)

spca2B <- spca(dat2B,xy=dat2B$other$xy,ask=FALSE,type=1,
plot=FALSE,scannf=FALSE,nfposi=1,nfnega=0)

spca2C <- spca(dat2C,xy=dat2C$other$xy,ask=FALSE,
type=1,plot=FALSE,scannf=FALSE,nfposi=0,nfnega=1)

spca3 <- spca(dat3,xy=dat3$other$xy,ask=FALSE,
type=1,plot=FALSE,scannf=FALSE,nfposi=1,nfnega=1)

spca4 <- spca(dat4,xy=dat4$other$xy,ask=FALSE,
type=1,plot=FALSE,scannf=FALSE,nfposi=1,nfnega=1)

# an auxiliary function for graphics
plotaux <- function(x,analysis,axis=1,lab=NULL,...){
neig <- NULL
if(inherits(analysis,"spca")) neig <- nb2neig(analysis$lw$neighbours)
xrange <- range(x$other$xy[,1])
xlim <- xrange + c(-diff(xrange)*.1 , diff(xrange)*.45)
yrange <- range(x$other$xy[,2])
ylim <- yrange + c(-diff(yrange)*.45 , diff(yrange)*.1)

s.value(x$other$xy,analysis$li[,axis],include.ori=FALSE,addaxes=FALSE,
cgrid=0,grid=FALSE,neig=neig,cleg=0,xlim=xlim,ylim=ylim,...)

par(mar=rep(.1,4))
if(is.null(lab)) lab = gsub("[P]","",x$pop)
text(x$other$xy, lab=lab, col="blue", cex=1.2, font=2)
add.scatter({barplot(analysis$eig,col="grey");box();
title("Eigenvalues",line=-1)},posi="bottomright",ratio=.3)
}

# plots
plotaux(dat2A,pca2A,sub="dat2A - PCA",pos="bottomleft",csub=2)
plotaux(dat2A,spca2A,sub="dat2A - sPCA glob1",pos="bottomleft",csub=2)

plotaux(dat2B,pca2B,sub="dat2B - PCA",pos="bottomleft",csub=2)
plotaux(dat2B,spca2B,sub="dat2B - sPCA glob1",pos="bottomleft",csub=2)

plotaux(dat2C,pca2C,sub="dat2C - PCA",pos="bottomleft",csub=2)
plotaux(dat2C,spca2C,sub="dat2C - sPCA loc1",pos="bottomleft",csub=2,axis=2)

par(mfrow=c(2,2))
plotaux(dat3,pca3,sub="dat3 - PCA axis1",pos="bottomleft",csub=2)
plotaux(dat3,spca3,sub="dat3 - sPCA glob1",pos="bottomleft",csub=2)
plotaux(dat3,pca3,sub="dat3 - PCA axis2",pos="bottomleft",csub=2,axis=2)
plotaux(dat3,spca3,sub="dat3 - sPCA loc1",pos="bottomleft",csub=2,axis=2)

plotaux(dat4,pca4,lab=dat4$other$sup.pop,sub="dat4 - PCA axis1",
pos="bottomleft",csub=2)
plotaux(dat4,spca4,lab=dat4$other$sup.pop,sub="dat4 - sPCA glob1",
pos="bottomleft",csub=2)
plotaux(dat4,pca4,lab=dat4$other$sup.pop,sub="dat4 - PCA axis2",
pos="bottomleft",csub=2,axis=2)
plotaux(dat4,spca4,lab=dat4$other$sup.pop,sub="dat4 - sPCA loc1",
pos="bottomleft",csub=2,axis=2)

# color plot
par(opar)
colorplot(spca3, cex=4, main="colorplot sPCA dat3")
text(spca3$xy[,1], spca3$xy[,2], dat3$pop)

colorplot(spca4, cex=4, main="colorplot sPCA dat4")
text(spca4$xy[,1], spca4$xy[,2], dat4$other$sup.pop)

# detach data
detach(spcaIllus)
}

Access and manipulate the population strata for genind or genlight objects.

Description

The following methods allow the user to quickly change the strata of a genind or genlight object.

Usage

strata(x, formula = NULL, combine = TRUE, value)

strata(x) <- value

nameStrata(x, value)

nameStrata(x) <- value

splitStrata(x, value, sep = "_")

splitStrata(x, sep = "_") <- value

addStrata(x, value, name = "NEW")

addStrata(x, name = "NEW") <- value

Arguments

x

a genind or genlight object

formula

a nested formula indicating the order of the population strata.

combine

if TRUE (default), the levels will be combined according to the formula argument. If it is FALSE, the levels will not be combined.

value

a data frame OR vector OR formula (see details).

sep

a character indicating the character used to separate hierarchical levels. This defaults to "_".

name

an optional name argument for use with addStrata if supplying a vector. Defaults to "NEW".

Details

Function Specifics

  • strata() - Use this function to view or define population stratification of a genind or genlight object.

  • nameStrata() - View or rename the different levels of strata.

  • splitStrata() - Split strata that are combined with a common separator. This function should only be used once during a workflow.

    • Rationale: It is often difficult to import files with several levels of strata as most data formats do not allow unlimited population levels. This is circumvented by collapsing all population strata into a single population factor with a common separator for each observation.

  • addStrata() - Add levels to your population strata. This is ideal for adding groups defined by find.clusters. You can input a data frame or a vector, but if you put in a vector, you have the option to name it.

Argument Specifics

These functions allow the user to seamlessly carry all possible population stratification with their genind or genlight object. Note that there are two ways of performing all methods:

  • modifying: strata(myData) <- myStrata

  • preserving: myNewData <- strata(myData, value = myStrata)

They essentially do the same thing except that the modifying assignment method (the one with the "<-") will modify the object in place whereas the non-assignment method will preserve the original object (unless you overwrite it). Due to convention, everything right of the assignment is termed value. To avoid confusion, here is a guide to the argument value for each function:

  • strata() value = a data.frame that defines the strata for each individual in the rows.

  • nameStrata() value = a vector or a formula that will define the names.

  • splitStrata() value = a formula argument with the same number of levels as the strata you wish to split.

  • addStrata() value = a vector or data.frame with the same length as the number of individuals in your data.

Details on Formulas

The preferred use of these functions is with a formula object. Specifically, a hierarchical formula argument is used to assign the levels of the strata. An example of a hierarchical formula would be:

~Country/City/Neighborhood

This convention was chosen as it becomes easier to type and makes intuitive sense when defining a hierarchy. Note: it is important to use hiearchical formulas when specifying hierarchies as other types of formulas (eg. ~Country*City*Neighborhood) will give incorrect results.

Author(s)

Zhian N. Kamvar

See Also

setPop genind as.genind

Examples

# let's look at the microbov data set:
data(microbov)
microbov

# We see that we have three vectors of different names in the 'other' slot. 
# ?microbov
# These are Country, Breed, and Species
names(other(microbov))

# Let's set the strata
strata(microbov) <- data.frame(other(microbov))
microbov

# And change the names so we know what they are
nameStrata(microbov) <- ~Country/Breed/Species

## Not run: 
# let's see what the strata looks like by Species and Breed:
head(strata(microbov, ~Breed/Species))

# If we didn't want the last column combined with the first, we can set
# combine = FALSE
head(strata(microbov, ~Breed/Species, combine = FALSE))

#### USING splitStrata ####

# For the sake of example, we'll imagine that we have imported our data set
# with all of the stratifications combined. 
setPop(microbov) <- ~Country/Breed/Species
strata(microbov) <- NULL

# This is what our data would look like after import.
microbov

# To set our strata here, we need to use the functions strata and splitStrata
strata(microbov) <- data.frame(x = pop(microbov))
microbov # shows us that we have "one" level of stratification
head(strata(microbov)) # all strata are separated by "_"

splitStrata(microbov) <- ~Country/Breed/Species
microbov # Now we have all of our strata named and split
head(strata(microbov)) # all strata are appropriately named and split.

## End(Not run)

Microsatellites genotypes of 781 swallowtail butterflies from 40 populations in Alberta and British Columbia, Canada

Description

This data set gives the genotypes of 781 swallowtail butterflies (Papilio machaon species group) for 10 microsatellites markers. The individuals are divided into 40 populations.

Format

swallowtails is a genind object containing 781 individuals, 10 microsatellite markers, and 40 populations.

Source

Julian Dupuis (University of Hawaii, USA)

References

Dupuis, J.R. & Sperling, F.A.H. Hybrid dynamics in a species group of swallowtail butterflies. Journal of Evolutionary Biology, 10, 1932–1951.

Examples

## Not run: 
data(swallowtails)
swallowtails

# conducting a DAPC (n.pca determined using xvalDapc, see ??xvalDapc)

dapc1 <- dapc(swallowtails, n.pca=40, n.da=200)

# read in swallowtails_loc.csv, which contains "key", "lat", and "lon"
# columns with column headers (this example contains additional columns
# containing species identifications, locality descriptions, and COI
# haplotype clades)

input_locs <- system.file("files/swallowtails_loc.csv", package = "adegenet")
loc <- read.csv(input_locs, header = TRUE)

# generate mvmapper input file, automatically write the output to a csv, and
# name the output csv "mvMapper_Data.csv"

out <- export_to_mvmapper(dapc1, loc, write_file = TRUE, out_file = "mvMapper_Data.csv")

## End(Not run)

Access allele counts or frequencies

Description

This accessor is used to retrieve a matrix of allele data. By default, a matrix of integers representing allele counts is returned. If freq is TRUE, then data are standardised as frequencies, so that for any individual and any locus the data sum to 1. The argument NA.method allows to replace missing data (NAs). This accessor replaces the previous function truenames as well as the function makefreq.

Usage

tab(x, ...)

## S4 method for signature 'genind'
tab(x, freq = FALSE, NA.method = c("asis", "mean", "zero"), ...)

## S4 method for signature 'genpop'
tab(x, freq = FALSE, NA.method = c("asis", "mean", "zero"), ...)

Arguments

x

a genind or genpop object.

...

further arguments passed to other methods.

freq

a logical indicating if data should be transformed into relative frequencies (TRUE); defaults to FALSE.

NA.method

a method to replace NA; asis: leave NAs as is; mean: replace by the mean allele frequencies; zero: replace by zero

Value

a matrix of integers or numeric

Examples

data(microbov)
head(tab(microbov))
head(tab(microbov,freq=TRUE))

Restore true labels of an object

Description

The function truenames returns some elements of an object (genind or genpop) using true names (as opposed to generic labels) for individuals, markers, alleles, and population.

Important: as of adegenet_2.0-0, these functions are deprecated as true labels are used whenever possible. Please use the function tab instead.

Usage

## S4 method for signature 'genind'
truenames(x)
## S4 method for signature 'genpop'
truenames(x)

Arguments

x

a genind or a genpop object

Value

If x$pop is empty (NULL), a matrix similar to the x$tab slot but with true labels.

If x$pop exists, a list with this matrix ($tab) and a population vector with true names ($pop).

Author(s)

Thibaut Jombart [email protected]

See Also

tab


Virtual classes for adegenet

Description

These virtual classes are only for internal use in adegenet

Objects from the Class

A virtual Class: No objects may be created from it.

Author(s)

Thibaut Jombart [email protected]