Admixture Estimates for Caracas, Venezuela, Based on Autosomal, Y-Chromosome, and mtDNA Markers

Abstract

The present Venezuelan population is the product of admixture of Amerindians, Europeans, and Africans, a process that was not homogeneous throughout the country. Blood groups, short tandem repeats (STRs), mtDNA, and Y-chromosome markers have been used successfully in admixture studies, but few such studies have been conducted in Venezuela. In this study we aim to estimate the admixture components of samples from two different socioeconomic levels from Caracas, Venezuela's capital city, compare their differences, and infer sexual asymmetry in the European Amerindian union patterns. Gene frequencies for blood groups ABO and Rh (CDE) and for the STRs VWA, F13A01, and FES/FPS and mtDNA and Y-chromosome haplogroups were studied in a sample of 60 individuals living in Caracas, taken from a private clinic (high socioeconomic level), and 50 individuals, also living in Caracas, drawn from a public maternity clinic (low socioeconomic level). The admixture analysis for the five autosomal markers gives a high European component (0.78) and an almost negligible African sub-Saharan component (0.06) for the high socioeconomic level, whereas for the low socioeconomic level the sub-Saharan, European, and Amerindian components were 0.21, 0.42, and 0.36, respectively. Estimates of admixture based on mtDNA and Y-chromosome markers reveal that the Amerindian contribution to these Caracas samples is almost entirely through females, because the Y-chromosome Amerindian and African sub-Saharan chromosomes found in this study were scarce. Our study reveals that the identification of the grandparents' geographic origin is an important methodological aspect to take into account in genetic studies related to the reconstruction of historical events.

Human Sociogenetics

“…They also agree with the asymmetric sexual composition (Valenzuela, 1975(Valenzuela, , 1983(Valenzuela, , 1997Valenzuela et al, 1978Valenzuela et al, , 1980Zemelman et al, 2002). The SGC and the asymmetry of mating is well documented at present with molecular genetic markers in Chile (Acuña et al, 2002;Cifuentes et al, 2004) and in other Latin American populations (Rodas et al, 2003;Martínez et al, 2007).…”

African ancestry is associated with risk of asthma and high total serum IgE in a population from the Caribbean Coast of Colombia

“…Additionally, the predominant European male contribution has been also described in earlier analyses using Y chromosome markers (Builes et al 2007). The European ancestry proportion estimated in this group is lower than those described in studies of Latin American populations as Mexicans, Afro-Brazilians, Venezuelan, Costa Rican, and Colombians (Bedoya et al 2006;Bonilla et al 2004a, b;Carvajal-Carmona et al 2000;Martinez-Marignac et al 2007;Martinez et al 2007b;Morera et al 2003;Muniz et al 2008;Salari et al 2005;Shriver et al 2003), but higher than those in Mexican mestizos from Mexico city and African Americans (Juarez-Cedillo et al 2008;Parra et al 1998;Shriver et al 2003). On the contrary, the African ancestry in this population located in the Caribbean Coast of Colombia is lower than those described in other African Caribbean (Benn-Torres et al 2008;Miljkovic-Gacic et al 2005), and African American populations ) but higher than those described in urban Afro-Brazilian, Venezuelan and Costa Rican populations (Martinez et al 2007b;Morera et al 2003;Muniz et al 2008).…”

Glucosa 6 fosfato deshidrogenasa en indígenas piaroas en zona endémica de malaria.

“…Con lo hallado en esta investigación se confirma la tendencia que muestran los análisis de variantes genéticas (polimorfirmos) de grupos sanguíneos y proteínas (principalmente), que en Venezuela, al igual que otros países latinoamericanos, es definitorio que las poblaciones sean bastante heterogéneas como resultado de los patrones de conquista y colonización, pues es muchos subgrupos poblacionales se evidencia la característica complejidad (respecto a la participación cuantitativa de los grupos étnicos y en la forma y dirección en que ocurrió el flujo de genes) que involucra la conformación y desarrollo histórico de los pueblos [41][42][43][44][45][46][47] .…”