Autosomal, mtDNA, and Y-chromosome diversity in Amerinds: Pre- and post-Columbian patterns of gene flow in South America

To evaluate sex-specific differences in gene flow between Native American p opulations from South America and between those populations and recent immi grants to the New World, we examined the genetic diversity at uni- and bipa rental genetic markers of five Native American populations from Colombia an d in published surveys from native South Americans. The Colombian populatio ns were typed for five polymorphisms in mtDNA, five restriction sites in th e beta -globin gene cluster, the DQA1 gene, and nine autosomal microsatelli tes. Elsewhere, we published results for seven Y-chromosome microsatellites in the same populations. Autosomal polymorphisms showed a mean G(ST) of 6. 8%, in agreement with extensive classical marker studies of South American populations. MtDNA and Y-chromosome markers resulted in G(ST) values of 0.1 8 and 0.165, respectively. When only Y chromosomes of confirmed Amerind ori gin were used in the calculations las defined by the presence of allele T a t locus DYS199), G(ST) increased to 0.22. G(ST) values calculated from publ ished data for other South American natives were 0.3 and 0.29 for mtDNA and Amerind Y chromosomes, respectively. The concordance of these estimates do es not support an important difference in migration rates between the sexes throughout the history of South Amerinds. Admixture analysis of the Colomb ian populations suggests an asymmetric pattern of mating involving mostly i mmigrant men and native women.