Ancestría genética y estratificación social en Montevideo, Uruguay

Several genetic studies have demonstrated that Uruguayan peoples are a trihybrid population, deriving from European/Mediterranean, Native American, and African ancestries that vary by region within the country. Studies on ancestries and origins that focus on Montevideo, the capital of Uruguay, are scarce and may differ from a general country-wide sample. We investigated the genetic origin of the population of Montevideo using a sample derived from a previously published study, in which we examined different factors that could influence ancestry estimations. The sample consisted of 269 women (cases and controls from a breast cancer research study). Haplogroups and hypervariable regions of the mitochondrial DNA, as well as nuclear ancestry informative markers, were analyzed. Differences in ancestral contributions were found when analyzing women attending public hospitals compared to those attending private clinics, with significant differences between Native American and European/Mediterranean contributions. After adjusting for health care system, we estimated the following contributions for the overall population of Montevideo: 24.6 % Native American, 67.7 % European, and 7.7 % African for maternal inheritance, and 11.1 % Native American, 81.4 % European, and 7.5 % African for biparental inheritance. We focused in particular on Native American and African contributions, and the results were discussed considering other sources of evidence. Due to the differences found between subsamples, caution is advised about sampling strategies and reference values to be used in further population studies.