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Mexico- Latest genetic study confirms Northern & Western regions to have the most European admixture
Forensic parameters and admixture in Mestizos from five geographic regions of Mexico based on 20 autosomal STRs (Powerplex 21 system)
Article (PDF Available) in International Journal of Legal Medicine 132(3) · March 2018
DOI: 10.1007/s00414-018-1810-z
Abstract
We analyzed Mestizo (admixed) population samples from different geographic regions of Mexico (n = 1283) with 20 autosomal STRs (PowerPlex® 21, Promega Corp.). Allele frequencies and forensic parameters from the Northwest, Northeast, West, Center, and Southeast regions are reported, as well as from the pooled Mexican population sample. The combined PD and PE for this 20 STR system were > 0.9999999999 and > 0.99999996593% in all five population samples, respectively. Analysis of molecular variance (AMOVA) of these Mexican population samples, plus Monterrey (Northeast) and Mexico (Center) Cities, showed low but significant differences among Mexican-Mestizos from the seven populations (Fst = 0.20%; p = 0.0000). Structure analysis showed the highest proportion of Native American ancestry in Mexico City, Center, and Southeast regions, respectively, which was in agreement with the estimated genetic distances represented in a MDS plot and a NJ tree. The best fit of population clusters (K = 4) obtained with the Structure software indicates that Mexican-Mestizos are mainly composed by European, African, and two Native American ancestries. The European and Native American ancestries displayed a contrary gradient, increasing toward the North-West and South-Southeast, respectively. These 20 autosomal STR loci improved the admixture estimation regarding previous studies with the 13 CODIS-STRs, as supported by the higher similarity with previous estimates based on genome-wide SNP. In brief, this study validates the confident use of the PowerPlex® 21 system for human identification purposes in Mestizo populations throughout the Mexican territory.
POPULATION DATA
Forensic parameters and admixture in Mestizos from five geographicregions of Mexico based on 20 autosomal STRs (Powerplex 21 system)J. A. Aguilar-Velázquez1,2&G. Martínez-Cortés1&A. Inclán-Sánchez3&A. F. Favela-Mendoza1&J. S. Velarde-Félix4,5&H. Rangel-Villalobos1Received: 7 November 2017 /Accepted: 22 February 2018#Springer-Verlag GmbH Germany, part of Springer Nature 2018AbstractWe analyzed Mestizo (admixed) population samples from different geographic regions of Mexico (n= 1283) with 20 autosomalSTRs (PowerPlex® 21, Promega Corp.). Allele frequencies and forensic parameters from the Northwest, Northeast, West,Center, and Southeast regions are reported, as well as from the pooled Mexican population sample. The combined PD and PEfor this 20 STR system were > 0.9999999999 and > 0.99999996593% in all five population samples, respectively. Analysis ofmolecular variance (AMOVA) of these Mexican population samples, plus Monterrey (Northeast) and Mexico (Center) Cities,showed low but significant differences among Mexican-Mestizos from the seven populations (Fst = 0.20%; p= 0.0000).Structure analysis showed the highest proportion of Native American ancestry in Mexico City, Center, and Southeast regions,respectively, which was in agreement with the estimated genetic distances represented in a MDS plot and a NJ tree. The bestfit ofpopulation clusters (K=4) obtained with the Structure software indicates that Mexican-Mestizos are mainly composed byEuropean, African, and two Native American ancestries. The European and Native American ancestries displayed a contrarygradient, increasing toward the North-West and South-Southeast, respectively. These 20 autosomal STR loci improved theadmixture estimation regarding previous studies with the 13 CODIS-STRs, as supported by the higher similarity with previousestimates based on genome-wide SNP. In brief, this study validates the confident use of the PowerPlex® 21 system for humanidentification purposes in Mestizo populations throughout the Mexican territory.Keywords STRs .Mexico .Mestizos .Structure .Powerplex .Mexican populationThe ~ 500 years of admixture among Native Americans,Europeans (mainly Spaniards), and Africans since theEuropean contact gave rise to the majority of the contempo-rary Mexican population (~ 90%), which commonly is re-ferred to as Mestizo [1,2]. The rest of the Mexican population(~ 10%) consists of Native American groups, who arrived noearly than 23,000 years ago and descend from the first settlersof the American continent [3]. Early studies on Mexican-Mestizos have described a trihybrid model to explain theirbiological diversity, where specific ancestries increase in dif-ferent geographical areas: the European in the North, theAmerindian in the Center and Southeast, and the African inthe coasts [4]. Subsequent studies with short tandem repeat(STR) loci have demonstrated a contrary genetic clinethroughout the Mexican territory, where the Amerindian an-cestry gradually increases from North-to-South and, converse-ly, the European ancestry gradually intensifies from South-to-North [1,2,5]. Interestingly, it has been claimed that thispattern approximates to the Pre-Hispanic Mesoamerican demography or, in other words, that recapitulates the NativeAmerican substructure [1,6]
Full article: https://www.researchgate.net/publica...plex_21_system
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Originally Posted by Bravado
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