Genetic admixture, relatedness, and structure patterns among Mexican populations revealed by the Y‐chromosome

Abstract

Y-linked markers are suitable loci to analyze genetic diversity of human populations, offering knowledge of medical, forensic, and anthropological interest. In a population sample of 206 Mestizo males from western Mexico, we analyzed two binary loci (M3 and YAP) and six Y-STRs, adding to the analysis data of Mexican Mestizos and Amerindians, and relevant worldwide populations. The paternal ancestry estimated in western Mexican-Mestizos was mainly European (60-64%), followed by Amerindian (25-21%), and African ( approximately 15%). Significant genetic heterogeneity was established between Mestizos from western (Jalisco State) and northern Mexico (Chihuahua State) compared with Mexicans from the center of the Mexican Republic (Mexico City), this attributable to higher European ancestry in western and northern than in central and southeast populations, where higher Amerindian ancestry was inferred. This genetic structure has important implications for medical and forensic purposes. Two different Pre-Hispanic evolutionary processes were evident. In Mesoamerican region, populations presented higher migration rate (N(m) = 24.76), promoting genetic homogeneity. Conversely, isolated groups from the mountains and canyons of the Western and Northern Sierra Madre (Huichols and Tarahumaras, respectively) presented a lower migration rate (N(m) = 10.27) and stronger genetic differentiation processes (founder effect and/or genetic drift), constituting a Pre-Hispanic population substructure. Additionally, Tarahumaras presented a higher frequency of Y-chromosomes without Q3 that was explained by paternal European admixture (15%) and, more interestingly, by a distinctive Native-American ancestry. In Purepechas, a special admixture process involving preferential integration of non-Purepecha women in their communities could explain contrary genetic evidences (autosomal vs. Y-chromosome) for this tribe.

Ancestry informative markers and admixture proportions in northeastern Mexico

“…21,29 The Y-SNPs estimations found in this study represent a significant difference from an earlier report analyzing M3 and YAP in western Mexican Mestizos (P¼0.046 and 0.0073), where these components were estimated in 60-64%, 25-21% and B15%, respectively. 20 Our results also showed a difference for the estimates of paternal contributions reported by Martinez-Marignac et al 21 in central Mexican Mestizo population using the M3 and M170 markers (60 and 40% for European and Native American contributions, respectively). However, these results are in agreement with the hypothesis of a higher European component in the northern region and, similarly, a higher Amerindian ancestry in the central and southeastern regions.…”

“…15 Native American, European and African paternal contributions were determined directly from haplogroup frequencies, considering worldwide phylogeographic information. 16,17 Into the haplogroup P (Q-R), the ancestral Amerindian lineage defined by P36 (haplogroup Q) was not genotyped; thus, it was estimated by the frequency of M3 and P36 in Native Americans and Hispanics, 18,19 as suggested by Rangel-Villalobos et al 20 …”

Analysis of admixture proportions in seven geographical regions of the state of Guerrero, Mexico

“…To be selected, the publications had to meet the following criteria: (1) published in peer‐reviewed journals, (2) with independent data, and (3) written in English. We do not include studies based on mtDNA or Y‐chromosome markers, or studies using short tandem repeats, also known as STRs, such as those conducted by Martínez‐Cortés et al (2012), Rangel‐Villalobos et al (2008), and Salazar‐Flores et al (2010). …”

Admixture and population structure in Mexican-Mestizos based on paternal lineages

“…This conclusion is in agreement with previous results suggesting that the increasing African ancestry is limited to particular coastal regions, but not to wide coastal areas of Mexico. 13 Similarly, states with presumable higher African ancestry (that is, Veracruz and Guerrero) have not shown a significant increase; they have only presented the highest interpopulation genetic variance of this ancestry. 5 This also could be Genetic relationships and population structure In general, the significant paternal population structure inferred here was similar to that observed in a previous study based on Y-STRs in Mexican-Mestizos, 15 in which three main regions are distinguished, including the following: (1) north-west, (2) center-south and (3) southeast.…”

“…11,12 The study of NRY biallelic variation for defining paternal lineages is particularly limited in Mestizos from Mexico and is even scarcer in Native American groups from this country. 13,14 Although the Y-STRs used in human identification have been employed to estimate paternal admixture in different Mexican-Mestizo populations, 15 these markers do not constitute the ideal tool for this purpose. 16 Available estimates based on Y-SNPs have been generated from a small number of populations, such as that of Mexico City, 17 and those of the states of Guerrero, 18 Jalisco 13 and Nuevo Leó n. 19 Moreover, with the exception of the latter report on Nuevo Leó n, the remaining studies were restricted to two or three Y-linked biallelic markers; thus, the wide diversity of paternal lineages evaluated by Y-SNPs is relatively unknown throughout the Mexican territory.…”