Browsing by Autor "Esther Esteban"

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Apolipoprotein E/C1/C4/C2 Gene Cluster Diversity in Two Native Andean Populations: Aymaras and Quechuas
(Wiley, 2012) Magdalena Gayà‐Vidal; Georgios Athanasiadis; Robert Carreras‐Torres; Marc Vía; Esther Esteban; Mercedes Villena; René Vásquez; Jean‐Michel Dugoujon; Pedro Moral
Summary The APOE/C1/C4/C2 gene cluster presents high relevance in lipid metabolism and, therefore, has important epidemiological implications. Here, we study for the first time the variation patterns of 25 polymorphisms (10 short tandem repeats, STRs, and 15 single nucleotide polymorphismas, SNPs) in two native Andean samples from Bolivia (45 Aymaras and 45 Quechuas) as well as one European sample (n = 41) as external reference. We estimated diversity parameters, linkage disequilibrium patterns, population structure, and possible selective effects. In general, diversity was low and could be partly attributed to selection (probably due to its physiological importance), since the APOE/C1/C4/C2 region was highly conserved compared to the flanking genes in both Bolivians and Europeans. Moreover, the lower gene diversity in Bolivians compared to Europeans for some markers might indicate different demographic histories. Regarding the APOE isoforms, in addition to ɛ3 (94%) and ɛ4 (5%), isoform ɛ2 (1%) was also detected in Bolivians. In relation to previous hypotheses, our results support that genetic drift or founder effects rather than selection for increased cholesterol absorption are the main factors that have shaped the distribution of APOE isoforms observed in South America.
Autosomal and X chromosome <i>Alu</i> insertions in Bolivian Aymaras and Quechuas: Two languages and one genetic pool
(Wiley, 2009) Magdalena Gayà‐Vidal; Jean‐Michel Dugoujon; Esther Esteban; Georgios Athanasiadis; Armando Rodríguez; Mercedes Villena; René Vásquez; Pedro Moral
Thirty-two polymorphic Alu insertions (18 autosomal and 14 from the X chromosome) were studied in 192 individuals from two Amerindian populations of the Bolivian Altiplano (Aymara and Quechua speakers: the two main Andean linguistic groups), to provide relevant information about their genetic relationships and demographic processes. The main objective was to determine from genetic data whether the expansion of the Quechua language into Bolivia could be associated with demographic (Inca migration of Quechua-speakers from Peru into Bolivia) or cultural (language imposition by the Inca Empire) processes. Allele frequencies were used to assess the genetic relationships between these two linguistic groups. Our results indicated that the two Bolivian samples showed a high genetic similarity for both sets of markers and were clearly differentiated from the two Peruvian Quechua samples available in the literature. Additionally, our data were compared with the available literature to determine the genetic and linguistic structure, and East-West differentiation in South America. The close genetic relationship between the two Bolivian samples and their differentiation from the Quechua-speakers from Peru suggests that the Quechua language expansion in Bolivia took place without any important demographic contribution. Moreover, no clear geographical or linguistic structure was found for the Alu variation among South Amerindians.