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How Plink LD-pruning selects which one of the pair SNPs in LD.

I am using plink to ld-pruning SNPs. But I wonder why plink always produce the same pruning results, even when I add a random seed.

Let's suppose, SNPs A and B are in LD. They can be also in LD with other SNPs. The SNPs in LD with A and the SNPs with B might be different. Thus, the first choice of A or B might produce different pruning SNP set. So, LD-pruning should produce a random result, really?

Here, I worry that Plink always produces a same result, it will produce a bias? Thank you for comments.

snp plink ld-pruning

1 answer

PLINK keeps the SNP with higher minor allele frequency, if the two MAFs are not identical. When there is a tie, the first SNP is kept.

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