Question: Population information for Fst in StAMPP
gravatar for aesculus
17 months ago by
aesculus10 wrote:


I want to calculate P values for pairwise Fst estimates among populations for my RADseq SNP dataset. I have been trying to use the R package StAMPP. The accepted input formats are .stampp, .vcf, .csv and an R genlight object. See:

The problem I have is that .vcf and genlight objects do not seem to contain a population column for individuals, but this is required by StaMPP to estimate allele frequencies (and then Fst estimates).

Is there a way to include population information in a vcf file or genlight object?

Alternatively, is there an easy way to produce a .stampp file? The format is hard to reproduce manually with a dataset of tens of thousands of SNPs.



Method 1

##1.1 Read fstat .dat into R and convert to genind object
genind<-read.fstat("f002-p3-r90-m10.dat", quiet=FALSE)

No genind2genlight command?

Method 2

##2.1 Read vcf file into into R
vcf<-read.vcfR("f002-p3-r60-m10.vcf", verbose = FALSE)
##2.2 Convert vcf into genlight object
x <- vcfR2genlight(vcf)
##2.3 Convert genlight to allele frequencies for StAMPP
data.freq<-stamppConvert(x, type = "genlight")

Error in pop.num[i] <- which(pop.names[i] == pops) : replacement has length zero

Need a population column in the vcf file or genlight object!

stampp snp fst adegenet vcf • 938 views
ADD COMMENTlink modified 16 months ago • written 17 months ago by aesculus10
gravatar for aesculus
16 months ago by
aesculus10 wrote:

Luke Pembleton very kindly provided this successful solution, should anyone else need it:

## as per your post 
##2.1 Read vcf file into into R 
vcf<-read.vcfR("g002-p3-r60-m10.vcf", verbose = FALSE) 
##2.2 Convert vcf into genlight object 
x <- vcfR2genlight(vcf) 

### convert genlight object to a matrix in stampp format 
x2 <- as.matrix(x) #convert genlight object to matrix 
sample <- row.names(x2) #sample names 

#pop.names <- pop(x) #extract ploidy info from genlight object (however this is not available when imported via a vcf file) 
#pop.names <- #provide a vector here of the same length of the number of samples, with a corresponding population name/id
#pop.names <- c(")
#e.g. c("popA", "popA", "popB", "popB", "popB", "popC", "popC") 

ploidy <- ploidy(x) #extract ploidy info from genlight object 
x2 = x2 * (1/ploidy) #convert allele counts to frequency 
x2[] = NaN 
format <- vector(length = length(sample))
#format id for the genotype data
format[1:length(format)] = "freq"  

x.stampp <-, pop.names, ploidy, format, x2)) #convert to basic r data.frame suitable to stamppConvert 

geno <- stamppConvert(x.stampp, 'r') 

#you should now be able to run all the stampp commands with 'geno' as the input object 
# e.g. fst <- stamppFst(geno)
ADD COMMENTlink written 16 months ago by aesculus10
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