Ancestralidade materna em populações da América do Sul: contrastando dados genéticos e históricos

• Autor(a) principal: Simão, Filipa Isabel Figueira
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/16115
• topic: mtDNA; Ancestry; South America; mtDNA; Ancestralidade; América do Sul; Genética de populações; Polimorfismo (Genética); América do Sul; População Aspectos genéticos; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA HUMANA E MEDICA

The cultural and ethnic heterogeneity present in South American populations is the result of extensive admixture processes, over the past centuries, among native Americans, European settlers (mainly Portuguese and Spanish) and African slaves. Because of its uniparental inheritance, polymorphisms located in the mitochondrial genome tell independent histories about maternal ancestors of the populations, working as a molecular record of the genealogical history and women migrations over several generations. The aim of the present study was to analyse the maternal genetic composition of three population groups of South America: admixed populations of Rio de Janeiro (Brazil) and Paraguay and native population of Peru, belonging to the Ashaninka group (Arawak language family). It was intended to investigate how the different historical events contributed to the current genetic composition of these populations as well as to evaluate their inter- and intra-population differences. Thus, the mtDNA control region of 675 individuals from South America was sequenced using the Sanger methodology. The continental origin of the maternal lineages was determined, based on the polymorphisms identified. In addition, 105 samples from individuals living in the department of Alto Paraná, Paraguay, and 20 samples from Ashaninka individuals were studied by massively parallel sequencing methodology, with the analysis of complete mtDNA molecule haplotypes. The Rio de Janeiro population presented a high proportion of African haplogroups (42% of the haplotypes belong to the macrohaplogroup L), the majority with a possible geographic origin in the Southwest region of Africa. For the Eurasian and Native American haplogroups found in Rio de Janeiro (representing 32% and 26% of the samples, respectively), it was not possible to determine a clear geographic origin or linguistic affiliation. The comparison of ancestry proportions, obtained for mtDNA and autosomal markers, pointed to the presence of population substructure in Rio de Janeiro. About 88% of the haplotypes observed in the Paraguayan population belong to Native American haplogroups. The comparison between the continental origin of the Paraguayan maternal lineages and the results obtained for autosomal ancestry markers, in 39 samples, supported the existence of admixture processes between Paraguayans and individuals from other populations, probably already admixed, where the men will have contributed with a high European ancestry. Moreover, the results obtained from the comparison of Alto Paraná mitogenomes with data available in the literature for other South American populations, indicated the influence of Tupi-Guarani natives, and of other linguistic groups. For the Ashaninka population, living in the Peruvian rainforest, no non-native maternal ancestry was observed, confirming the geographic isolation of this native group. The sequencing results of mitogenome for 20 Ashaninka samples, belonging to haplogroup B2 + 16051G + 16129A + 152C, not only support the theories about the origin of the Arawak linguistic family, but also revealed a possible south dispersal route in the subcontinent. With the results obtained in the present study, it is evident the differential contribution of the maternal components in the three populations studied, with an association with their particular historical events.