1Anthropology, University of Pennsylvania, Philadelphia, PA, 2Toxicology, CINVESTAV-IPN Mexico City, Mexico, 3Molecular Biomedicine, CINVESTAV-IPN Mexico City, Mexico, 4The National Geographic Society
Friday 4:00-4:15, 200ABC
Home to the Aztec Empire, Central Mexico was the most densely populated area of Mesoamerica in the 16th century. Today, more than half a million indigenous people from numerous ethnic groups still inhabit the region, including the Otomi and Chichimeca (Oto-Manguean languages), the Nahua (Uto-Aztecan language), and the Tepehua (Totonocan language). To assess the genetic diversity of indigenous Mexicans and infer prehistoric patterns of interactions amongst them, we analyzed genetic variation in 536 individuals from twenty-three communities in Guanajuato, Hidalgo, Morelos and Queretaro states. Mitochondrial DNA (mtDNA) diversity was characterized through control region sequencing and coding-region SNP genotyping; Y-chromosome diversity through SNP and STR genotyping; and autosomal diversity through SNP genotyping. MtDNA analyses revealed a high frequency (>98%) and considerable diversity of the four major Native American haplogroups (A2, B2, C1 and D1), along with the presence of D4h3 among the Otomi. Y-chromosome analysis also showed a high frequency (~60%) and haplotype diversity for indigenous haplogroups Q-M3 and Q-L54 among these four populations, while autosomal SNP analysis revealed a high percentage (>80%) of indigenous markers across all ethnic groups. We used these data to examine genetic differentiation and gene flow amongst ethnic groups, and to assess genetic diversity within their different language families. Overall, the high frequency and great diversity of indigenous mtDNA and Y-chromosome haplotypes in Central Mexico suggests the region may have been a center for population growth and expansion for many millennia. Our data further suggest that indigenous Mexican populations have experienced relatively limited historic admixture.
This project was supported by funds provided by CONACYT (RG), the National Geographic Society and the University of Pennsylvania (TGS).