Interethnic variability and admixture in Latin America - social implications

Salzano, Francisco M.

doi:10.15517/rbt.v1i2.15273

Cited by 19 publications

(20 citation statements)

References 45 publications

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“…All combinations of bilocal, patrilocal or matrilocal societies were simulated corresponding to a total of nine scenarios (see the electronic supplementary material, table S1), using the mSR parameter. As in Currat & Excoffier [17], we assumed unidirectional admixture, from the HG to the farmer layer, in agreement with anthropological data suggesting that asymmetrical gene flow occurs when a dominant group invades a new region, as is supposed to have happened during the Bantu expansion [33] or in the colonization of Brazil by Europeans [34]. Five values of g (0, 0.25, 0.5, 0.75 and 1) were used for each of the nine scenarios above, for a total of 45 different simulation sets carried out in the 10Â10 lattices.…”

Section: (B) Neolithic Transition Modelsupporting

confidence: 77%

Investigating sex-biased migration during the Neolithic transition in Europe, using an explicit spatial simulation framework

et al. 2012

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Cultural practices can deeply influence genetic diversity patterns. The Neolithic transitions that took place at different times and locations around the world led to major cultural and demographic changes that influenced and therefore left their marks on human genetic diversity patterns. Several studies on the European Neolithic transition suggest that mitochondrial DNA (mtDNA) and Y-chromosome data can exhibit different patterns, which could be owing to different demographic histories for females and males. Archaeological and anthropological data suggest that the transition from hunter-gatherers (HGs) to farmers' societies is probably associated with changes in social organization, particularly in post-marital residence (PMR) rules (i.e. patrilocality, matrilocality or bilocality). The movements of humans and genes associated with these rules can be seen as sex-biased short-range migrations. We developed a new individual-based simulation approach to explore the genetic consequences of 45 different scenarios, where we varied the patterns of PMR and admixture between HGs and farmers. We recorded mtDNA and Y-chromosome data and analysed their diversity patterns within and between populations, through time and space. We also collected published mtDNA and Y-chromosome data from European and Near-Eastern populations in order to identify the scenarios that would best explain them. We show that: (i) different PMR systems can lead to different patterns of genetic diversity and differentiation, (ii) asymmetries between mtDNA and Y-chromosome can be owing to different behaviours between males and females, but also to different mutations rates, and (iii) patrilocality in farmers explains the present patterns of genetic diversity better than matrilocality or bilocality. Moreover, we found that (iv) the genetic diversity of farmers change depending on the HGs PMR rules even though they are assumed to disappear more than 5000 years ago in our simulations.

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Section: (B) Neolithic Transition Modelsupporting

confidence: 77%

Investigating sex-biased migration during the Neolithic transition in Europe, using an explicit spatial simulation framework

et al. 2012

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“…This is the case for the Brazilian population that is the result of more than 500 years of social, commercial and physical contact between Europeans, Native Americans and Africans. 1 These peoples met and mated with each other in distinct ways that varied across the continental expanse of the country, giving rise to a multiethnic and highly admixed population. 2 In Brazil, skin color has been used as a phenotypic surrogate for biogeographical ancestry in the scientific literature, but with recognition of the influence of socioeconomics, familial origin and ethnic identity.…”

Section: Introductionmentioning

confidence: 99%

The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions

et al. 2014

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The degree of admixture in Brazil between historically isolated populations is complex and geographically variable. Studies differ as to what the genetic and phenotypic consequences of this mixing have been. In Northeastern Brazil, we enrolled 522 residents of Salvador and 620 of Fortaleza whose distributions of self-declared color were comparable to those in the national census. Using the program Structure and principal components analysis there was a clear correlation between biogeographic ancestry and categories of skin color. This correlation with African ancestry was stronger in Salvador (r=0.585; P<0.001) than in Fortaleza (r=0.236; P<0.001). In Fortaleza, although self-declared blacks had a greater proportion of European ancestry, they had more African ancestry than the other categories. When the populations were analyzed without pseudoancestors, as in some studies, the relationship of 'race' to genetic ancestry tended to diffuse or disappear. The inclusion of different African populations also influenced ancestry estimates. The percentage of unlinked ancestry informative markers in linkage disequilibrium, a measure of population structure, was 3-5 times higher in both Brazilian populations than expected by chance. We propose that certain methods, ascertainment bias and population history of the specific populations surveyed can result in failure to demonstrate a correlation between skin color and genetic ancestry. Population structure in Brazil has important implications for genetic studies, but genetic ancestry is irrelevant for how individuals are treated in society, their health, their income or their inclusion. These track more closely with perceived skin color than genetic ancestry.

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“…Incluso en grupos étnicos como los han de China, ha sido necesario incluir otras variables predictoras como el gen CYP4F2 (17). La situación se complica en poblaciones muy mezcladas, como la latinoamericana, en la cual la contribución relativa de africanos, amerindios y europeos varía de acuerdo con circunstancias históricas (18). No parece haber, entonces, una única fórmula idónea, por lo que deben considerarse los factores locales a la hora de escoger el algoritmo farmacogenético más apropiado (19).…”

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Predicción de sensibilidad a la warfarina basada en VKORC1 y CYP2C9 en pacientes de diferentes lugares de Colombia

2015

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Contribución de los autores:Ricardo A. Cifuentes: concepción del proyecto, genotipificación y análisis de datos Todos los autores participaron en la captación de los pacientes, la recolección de datos, la interpretación de los resultados y la escritura del manuscrito.Predicción de la sensibilidad a la warfarina con base en polimorfismos de los genes VKORC1 y CYP2C9 en pacientes colombianos Introducción. La validación de los factores predictores de la sensibilidad a la warfarina es importante para evitar las hemorragias asociadas con la terapia anticoagulante. En los estudios previos hechos en Colombia con polimorfismos de los genes VKORC1 y CYP2C9, se reportaban algoritmos con rendimientos diferentes para explicar la variación de las dosis, pero no se evaluaba la predicción de la sensibilidad a la warfarina. Objetivo. Determinar la exactitud del análisis farmacogenético de los polimorfismos *2 y *3 en el gen CYP2C9 y 1639G>A en el gen VKORC1 para predecir la sensibilidad a la warfarina en pacientes del Hospital Militar Central, un centro de referencia que atiende pacientes de diferentes lugares de Colombia. Materiales y métodos. Se recopilaron los datos demográficos y clínicos de 130 pacientes que habían recibido una dosis estable de warfarina durante más de dos meses. Se obtuvieron sus genotipos mediante un análisis de curvas de fusión, y, después de verificar el equilibrio de Hardy-Weinberg de los polimorfismos, se hizo un análisis estadístico con enfoque multivariado y predictivo.Resultados. Se construyó un modelo farmacogenético que explicó el 52,8 % de la variación de la dosis (p<0,001), solo 4 % por encima del rendimiento obtenido con los mismos datos usando el algoritmo del International Warfarin Pharmacogenetics Consortium. El modelo predictivo de sensibilidad logró 77,8 % de exactitud e incluyó como factores la edad (p=0,003), los polimorfismos *2 y *3 (p=0,002) y el polimorfismo 1639G>A (p<0,001). Conclusiones. Estos resultados en una población mestiza colombiana respaldan la validez de la predicción de la sensibilidad a la warfarina basada en los polimorfismos de los genes VKORC1 y CYP2C9. Prediction of sensitivity to warfarin based on VKORC1 and CYP2C9 polymorphisms in patients from different places in Colombia Introduction: In the search to prevent hemorrhages associated with anticoagulant therapy, a major goal is to validate predictors of sensitivity to warfarin. However, previous studies in Colombia that included polymorphisms in the VKORC1 and CYP2C9 genes as predictors reported different algorithm performances to explain dose variations, and did not evaluate the prediction of sensitivity to warfarin. Objective: To determine the accuracy of the pharmacogenetic analysis, which includes the CYP2C9 *2 and *3 and VKORC1 1639G>A polymorphisms in predicting patients' sensitivity to warfarin at the Hospital Militar Central, a reference center for patients born in different parts of Colombia. Materials and methods: Demographic and clinical data were obtained from 130 patients with stable doses of warfari...

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Interethnic variability and admixture in Latin America - social implications

Cited by 19 publications

References 45 publications

Investigating sex-biased migration during the Neolithic transition in Europe, using an explicit spatial simulation framework

Investigating sex-biased migration during the Neolithic transition in Europe, using an explicit spatial simulation framework

The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions

Predicción de sensibilidad a la warfarina basada en VKORC1 y CYP2C9 en pacientes de diferentes lugares de Colombia

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