Genetic structure of Mendoza province population inferred from autosomal and Y-chromosome STRs analysis

Abstract

The population of Mendoza, like the entire population of Argentina, has a heterogeneous genetic constitution. It is the result of two major contributors; Native Americans and Europeans and, in a lesser degree, Western Africans, brought to the territory as slaves during colonial times. In order to investigate the proportion of genetic contributions of the parental populations to nowadays population of Mendoza, a set of 13 autosomal and 9 Y-STRs routinely used in forensic typing were selected. Although these markers are not the best suited for tracing ancestry, they might provide clues about the genetic structure of a population. A total of 242 male unrelated donors inhabiting Mendoza province were analyzed and compared with Argentinean Amerindian, Caucasian and African-American, reference samples. Genetic distance, based on R st values, and STRUCTURE analysis were performed for both polymorphic systems. Our results demonstrate a tri-parental genetic contribution whose proportions differs between autosomal or Y-STRs markers. Autosomal STRs denoted 46.8% European, 31.6% Native American and 21.5% African contributions. Instead, Y-STRs showed 67% European, 21% Amerindian, and 12% African ancestral lineages. These results are consistent with the history of submission undergone by the native populations during the conquest of the Americas and underscore the impact of the European male genetic contribution to extant population of Argentina. Probably our results underestimate the Caucasian and overestimate the Native American and African contributions since the polymorphisms employed are not as sensitive as the ancestry informative markers (AIMs).