X-chromosome lineages and the settlement of the Americas.
Most genetic studies on the origins of Native Americans have examined data from mtDNA and Y-chromosome DNA. To complement these studies and to broaden our understanding of the origin of Native American populations, we present an analysis of 1,873 X-chromosomes representing Native American (n = 438) and other continental populations (n = 1,435). We genotyped 36 polymorphic sites, forming an informative haplotype within an 8-kb DNA segment spanning exon 44 of the dystrophin gene. The data reveal continuity from a common Eurasian ancestry between Europeans, Siberians, and Native Americans. However, the loss of two haplotypes frequent in Eurasia (18.8 and 7%) and the rise in frequency of a third haplotype rare elsewhere, indicate a major population bottleneck in the peopling of the Americas. Although genetic drift appears to have played a greater role in the genetic differentiation of Native Americans than in the latitudinally distributed Eurasians, we also observe a signal of a differentiated ancestry of southern and northern populations that cannot be simply explained by the serial southward dilution of genetic diversity. It is possible that the distribution of X-chromosome lineages reflects the genetic structure of the population of Beringia, itself issued from founder effects and a source of subsequent southern colonization(s).
Bourgeois
Stephane
S
Centre de Recherche de l'Hôpital Sainte-Justine, Montréal, QC H3T 1C5, Canada.
Yotova
Vania
V
Wang
Sijia
S
Bourtoumieu
Sylvie
S
Moreau
Claudia
C
Michalski
Roman
R
Moisan
Jean-Paul
JP
Hill
Kim
K
Hurtado
Ana M
AM
Ruiz-Linares
Andres
A
Labuda
Damian
D
D000569:Americas; D041321:Chromosomes, Human, X; D005260:Female; D040961:Genetic Drift; D005843:Geography; D006239:Haplotypes; D006801:Humans; D007198:Indians, North American / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic; D025341:Principal Component Analysis