Heterogeneity in Genetic Admixture across Different Regions of Argentina

Abstract

The population of Argentina is the result of the intermixing between several groups, including Indigenous American, European and African populations. Despite the commonly held idea that the population of Argentina is of mostly European origin, multiple studies have shown that this process of admixture had an impact in the entire Argentine population. In the present study we characterized the distribution of Indigenous American, European and African ancestry among individuals from different regions of Argentina and evaluated the level of discrepancy between self-reported grandparental origin and genetic ancestry estimates. A set of 99 autosomal ancestry informative markers (AIMs) was genotyped in a sample of 441 Argentine individuals to estimate genetic ancestry. We used non-parametric tests to evaluate statistical significance. The average ancestry for the Argentine sample overall was 65% European (95%CI: 63–68%), 31% Indigenous American (28–33%) and 4% African (3–4%). We observed statistically significant differences in European ancestry across Argentine regions [Buenos Aires province (BA) 76%, 95%CI: 73–79%; Northeast (NEA) 54%, 95%CI: 49–58%; Northwest (NWA) 33%, 95%CI: 21–41%; South 54%, 95%CI: 49–59%; p<0.0001] as well as between the capital and immediate suburbs of Buenos Aires city compared to more distant suburbs [80% (95%CI: 75–86%) versus 68% (95%CI: 58–77%), p = 0.01]. European ancestry among individuals that declared all grandparents born in Europe was 91% (95%CI: 88–94%) compared to 54% (95%CI: 51–57%) among those with no European grandparents (p<0.001). Our results demonstrate the range of variation in genetic ancestry among Argentine individuals from different regions in the country, highlighting the importance of taking this variation into account in genetic association and admixture mapping studies in this population.

Asociación entre polimorfismos del gen NAT2 y fisura labiopalatina no sindrómica en Argentina

“…Se sabe que la población contemporánea argentina es el resultado de múltiples interacciones ocurridas entre la población nativa del continente con poblaciones europeas y africanas 17,18 . Para controlar el factor de confusión ancestralidad en nuestra muestra empleamos un diseño de tríos caso-progenitores donde el caso es comparado con un pseudocontrol pareado étnicamente 11 .…”

Random inbreeding, isonymy, and population isolates in Argentina

“…In the northwest predominate, the Native American component, in the south the European. The African component is minority (Wang et al 2008;Avena et al 2012), Based on the frequency of surnames in each department the expected isonymy was estimated assuming random mating,…”

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

“…Se emplearon los datos del trabajo realizado por Avena et al (2012) en el que, utilizando 99 AIMs, se genotipificaron 441 individuos provenientes de distintas regiones de Argentina (Noroeste, Noreste, Centro y Sur), siendo la ancestría promedio 65% euroasiática, 31% nativoamericana y 4% subsahariana. Sobre ese total de marcadores, se realizaron muestreos aleatorios e independientes para obtener conjuntos de 10, 20, 30 y 50 AIMs.…”

“…Para cada componente por separado, se analizó la correlación entre la ancestría individual obtenida con cada conjunto de AIMs y la calculada a partir de los 99 en el trabajo de Avena et al (2012). Para cada individuo, se promediaron los valores de ancestría obtenidos en las cinco corridas realizadas con cada conjunto de marcadores.…”

“…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).…”