Linguistic and maternal genetic diversity are not correlated in native mexicans

Abstract

Mesoamerica, defined as the broad linguistic and cultural area from middle southern Mexico to Costa Rica, might have played a pivotal role during the colonization of the/nAmerican continent. It has been suggested that the Mesoamerican isthmus could have played an important role in severely restricting prehistorically gene flow between North and South/nAmerica. Although the Native American component has been already described in admixed/nMexican populations, few studies have been carried out in native Mexican populations. In this/nstudy we present mitochondrial DNA (mtDNA) sequence data for the first hypervariable region (HVR-I) in 477 unrelated individuals belonging to eleven different native populations from Mexico. Almost all the Native Mexican mtDNAs could be classified into the four pan-Amerindian haplogroups (A2, B2, C1 and D1); only three of them could be allocated to the rare Native American lineage D4h3. Their haplogroup phylogenies are clearly star-like, as expected from relatively young populations that have experienced diverse episodes of genetic drift (e.g. extensive isolation, genetic drift and founder effects) and posterior population expansions. In agreement with this observation is the fact that Native Mexican populations show a high degree of heterogeneity in their patterns of haplogroup frequencies. Haplogroup/nX2a was absent in our samples, supporting previous observations where this clade was only detected in the American northernmost areas. The search for identical sequences in the American continent shows that, although Native Mexican populations seem to show a closer relationship to North American populations, they cannot be related to a single geographical region within the continent. Finally, we did not find significant population structure on the maternal lineages when considering the four main and distinct linguistic groups represented in our Mexican samples (Oto-Manguean, Uto-Aztecan, Tarascan, and Mayan), suggesting that genetic divergence predates linguistic diversification in Mexico.