Extraction of subset of population from Ancestrymap files (.geno, .ind., .snp)

Question

[vicky]

Hi

I have got the ancestry map files (.geno, .ind, .snp) files with 1000 individuals from 200 populations. I want to extract a subset (20) of populations from these files. Is there any program to do this. I want run later SmartPca over these files.

thanks