Genética de populações e reinterpretação da história demográfica de remanescentes de quilombos: uma comparação entre três populações do nordeste brasileiro

AUTOR(ES)

Carlos Eduardo Guerra Amorim

DATA DE PUBLICAÇÃO

2009

RESUMO

The remanescentes de quilombos are multiethnic societies whose origins are related to the presence of African slaves in Brazil. The demographic history of these populations has been studied using historical, demographic, ethnographic and genetic sources. The present work aims to evaluate the origin and the impact of recent and ancient waves of immigration upon the genetic constitution of the remanescentes de quilombos of Mocambo, Rio das Rãs and Sacutiaba. For this purpose, demographic and genetic parameters were analyzed. The demographic parameters are sex, matrimonial status and place of birth, and the genetic parameters are allelic and genotypic frequencies of 16 autosomal genetic markers. The genetic data generated for each population were used in a comparison between the proportions of natives and immigrants in each population, as well to eight Brazilian admixed populations and the parental groups of Africans, Amerindians and Europeans. A considerable proportion of immigrants was observed in all communities, most of which were women, indicating that marriage is one of the primary factors shaping the current picture. As for the genetic data, no significant differences were found between the proportions of immigrants and natives. A predominance of endogamic marriages was found, although it was not sufficient to substantially alter the genetic structure of the populations. The results indicate the existence of continuous gene flow in these populations, with the predominant genetic contribution being the African one in all analyses. Mocambo showed the most complex admixture estimates, with the lowest African proportion (52.2%). It is possible that at some point in their histories, these populations were isolated. However, the barrier to gene flow nowadays has already been quite dissolved. The impact of immigration was low, which may be related to the homogenization caused by the active gene flow during most of the history of these populations. Furthermore, the data corroborate other historical sources which indicate the prominence of Africans and admixture between Africans and other peoples during the formation of these communities.

ASSUNTO(S)

mistura genética genetica humana e medica genetic admixture aim aim fluxo gênico casamento migração migration marriage gene flow

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