a, f3 statistics of the form f3(San; X, USR1), for each population in the genotype panel. Warmer colours represent greater shared drift between a population (X) and USR1. b, D statistics of the form D(Native American, Aymara; USR1, Yoruba) (points). The Andean Aymara were used to represent SNA. *Native American populations with Asian admixture (|Z| for D(H1, Aymara; Han, Yoruba) > 3.3) (Supplementary Fig. 5a). Error bars represent 1 and approximately 3.3 standard errors (P ≈ 0.001). Native American populations were grouped by language family1. c, Quantile–quantile plot comparing observed Z scores to the expected normal distribution under the null hypothesis (H0), for all possible D(Native American, USR1; Siberian1, Siberian2). Colours correspond to the Z score obtained for D(H1, Aymara; Han, Yoruba). The expected normal distribution under the null hypothesis was computed for all groups jointly (Supplementary Information section 10.4). Thick and thin lines represent a Z score of approximately 3.3 (P ≈ 0.001) and a Z score of approximately 4.91 (P ≈ 0.01 after applying a Bonferroni correction for 11,322 tests). The bottom-right panel shows the expected tree under the null hypothesis. d, Admixture proportions estimated by ADMIXTURE20 assuming K = 20 ancestral populations. Bars represent individuals, and colours represent admixture proportions from each ancestral component. Admixture proportions in ancient genomes (wider bars) were estimated using a genotype likelihood-based approach21. Nat. Am., Native American; Sib., Siberian.