Substantial native American female contribution to the population of Tacuarembó, Uruguay, reveals past episodes of sex‐biased gene flow

Abstract

For many years it has been assumed that the population of Uruguay is almost exclusively European-derived and that the biological contribution of the native population as well as of individuals of African descent is negligible. Several recent studies based on a variety of genetic markers, mostly morphological and serological markers, have produced quite a different picture of the constitution of the Uruguayan population. The Native American contribution varies from 1-20%, while the African contribution ranges from 7-15%, in different regions of the country. In the present study we examine the way the admixture process took place in Uruguay by analyzing the ancestry of maternal lineages in a sample from the northern city of Tacuarembó. To accomplish this goal we typed mitochondrial DNA (mtDNA) markers of Native American, African, and European origin and estimated the proportions of each parental group in the admixed population. We found that 62% of all mtDNA haplogroups were of Native American descent, a surprising figure considering the "European roots" of the country. Consequently, this result assimilates Uruguay to the rest of Latin American populations where sex-biased gene flow between European men and Native American women has been the rule. We further analyzed the distribution of the four major founding mitochondrial lineages in Tacuarembó and compared it to other South American populations. We discuss our findings in the light of historical records and assess the need for additional genetic studies.

Pre- and Post-Columbian Gene and Cultural Continuity: The Case of the <i>Gaucho</i> from Southern Brazil

“…This result supports the idea that its presence in the Gaucho can be attributed to Guarani inheritance. The same can be suggested for lineage 16111T-16189C-16223T-16290T-16319A-16362C, which was also detected in admixed populations from Southeast Brazil and Uruguay, areas with some influence of Tupi-Guarani tribes [33,56] .…”

“…3 and 4 ). Uruguay is the only South American country where independent Native American populations no longer exist [56] . Recent studies, however, revealed that people from this country experienced sex-biased unions during the Colonial Period, similar to those which occurred in other Latin American populations [56,57] .…”

“…This number is intermediate to those observed in individuals morphologically identified as white ( ϳ 3%) or black ( ϳ 80%) in distinct regions of Rio Grande do Sul [21,59] . Tacuarembó received fugitive slaves from nearby Rio Grande do Sul, which can explain the presence of African sequences (17%) in this Uruguayan population [56] . The samples were obtained from ancient DNA; the lineages that could represent artefacts [70] were excluded from this analysis.…”

“…The European contribution is the highest in the South, except for the Gauchos and Tacuarembó. This European influence is not surprising, since southern Brazil and Uruguay had important and massive European migratory waves that occurred mostly during the second half of the 19th and the beginning of the 20th centuries [56,58] . Different from what occurred in the earlier centuries of colonization, when almost only European men migrated, this most recent major migratory movement involved both couples and families [58] .…”

“…The other carries three private mutations (G ] A at position 16145; C ] T at 16179; C ] T at 16295) and it is difficult to define its origin since it belongs to an extensive D1 sub-haplogroup found in Native and admixed populations from Venezuela, Colombia, Brazil and Uruguay [16,33,55,56,73,[75][76][77] .…”