Table 2 Relatedness and population clustering. Estimates are based on PLINK genotype calls where the ‘identical by state’ (IBS) genotype pattern was estimated for a pair of samples and the test for population clustering was conducted using pairwise population concordance (PPC). The genotype pattern for each variable site is estimated as the sharing of two ancestral alleles, one ancestral and one derived allele, and two derived alleles between the individuals. The IBS ratios indicate that all pairs (ratios > 2.0) are more related than expected under random mating. The PPC results indicate we cannot reject the null hypothesis (ratio = 2) that all three individuals belong to the same population (p = 0.05)

From: The inference of gray whale (Eschrichtius robustus) historical population attributes from whole-genome sequences