Interpret PCA as combinations of SNPs

Question

[Tam]

Hi everyone,

I understand that the PCA in SNPRelate summarizes the genetic variance of the population, but I would love to know how one can derive the genetic makeup (SNPs) that correspond with the principal components. I tried reading the code from

https://github.com/zhengxwen/SNPRelate/blob/master/src/genPCA.cpp

but it's not so easy. If there's a source where I can read the mathematics behind this code (how the principal components are computed from the SNPs dataset), I would love to see it as well.

Many thanks.

[Alex Reynolds]

The first paper here describes some of the procedure: https://github.com/zhengxwen/SNPRelate#citations There are references there that might also be generally useful.