Fig. 1.

(A) Scatterplot of the 367 individuals sampled from 20 Indian populations by the first two PCs extracted from genome-wide genotype data. The Andamanese populations (JRW and ONG) cluster together and are widely separated from mainland populations. (B) Ancestries of individuals estimated using ADMIXTURE with two ancestral components. The 367 individuals are clustered into two distinct groups: the mainlanders (red) and Andamanese islanders (green). (Ancestries of individuals estimated using ADMIXTURE for K = 2, 3, and 4 and related results are in SI Appendix.)