High interpopulation homogeneity in Central Argentina as assessed by Ancestry Informative Markers (AIMs)

Abstract

The population of Argentina has already been studied with regard to several genetic markers, but much more data are needed for the appropriate definition of its genetic profile. This study aimed at investigating the admixture patterns and genetic structure in Central Argentina, using biparental markers and comparing the results with those previously obtained by us with mitochondrial DNA (mtDNA) in the same samples. A total of 521 healthy unrelated individuals living in 13 villages of the Córdoba and San Luis provinces were tested. The individuals were genotyped for ten autosomal ancestry informative markers (AIMs). Allele frequencies were compared with those of African, European and Native American populations, chosen to represent parental contributions. The AIM estimates indicated a greater influence of the Native American ancestry as compared to previous studies in the same or other Argentinean regions, but smaller than that observed with the mtDNA tests. These differences can be explained, respectively, by different genetic contributions between rural and urban areas, and asymmetric gene flow occurred in the past. But a most unexpected finding was the marked interpopulation genetic homogeneity found in villages located in diverse geographic environments across a wide territory, suggesting considerable gene flow.

Fine-scale genomic analyses of admixed individuals reveal unrecognized genetic ancestry components in Argentina

“…The PCA shows, as expected, that Argentinean individuals have different proportions of European, Native American and, much less represented, African ancestry ( S1A Fig ). This pattern, which has already been documented in other admixed populations in South America [33, 45], including in Argentina [14–17,34] supports the heterogeneous genetic origins throughout the country. The third and the fifth principal components discriminate three different main Native American ancestries that are also represented in the Argentinean samples.…”

“…The first systematic investigation of human genetic variation in the country focused on a limited number markers either uniparental (mtDNA, Y-STRs, Y-SNP; [2–11] or autosomal (Short Tandem Repeats, Ancestry Informative Markers, Alu sequences, indels, and blood groups [12–17]). Studies based on autosomal markers identified an important inter-individual heterogeneity for the African, Native American and European genetic ancestry proportions [12–17].…”

“…The first systematic investigation of human genetic variation in the country focused on a limited number markers either uniparental (mtDNA, Y-STRs, Y-SNP; [2–11] or autosomal (Short Tandem Repeats, Ancestry Informative Markers, Alu sequences, indels, and blood groups [12–17]). Studies based on autosomal markers identified an important inter-individual heterogeneity for the African, Native American and European genetic ancestry proportions [12–17]. Accordingly, most of the studies based on uniparental markers showed large differences in the genetic composition of Argentinean populations, accounting for the different demographic histories within the country [2,3,18–21,4–10,17].…”

“…Studies based on autosomal markers identified an important inter-individual heterogeneity for the African, Native American and European genetic ancestry proportions [12–17]. Accordingly, most of the studies based on uniparental markers showed large differences in the genetic composition of Argentinean populations, accounting for the different demographic histories within the country [2,3,18–21,4–10,17]. A recently published book compiles most of these studies and others to gives a general view about the admixture in Argentinean populations [22].…”

Evaluación del número mínimo de marcadores para estimar ancestría individual en una muestra de la población argentina

“…Estudios previos muestran que existen importantes diferencias regionales, dadas tanto por las cantidades relativas de cada componente como por la intensidad y dirección del proceso de mestizaje (Avena et al 2012;Corach et al 2010;García et al 2011, entre otros).…”