RESUMO
The formation of the Brazilian Amazonian population has historically involved three main ethnic groups, Amerindian, African and European. This has resulted in genetic investigations having been carried out using classical polymorphisms and molecular markers. To better understand the genetic variability and the micro-evolutionary processes acting in human groups in the Brazilian Amazon region we used mitochondrial DNA to investigate 159 maternally unrelated individuals from five Amazonian African-descendant communities. The mitochondrial lineage distribution indicated a contribution of 50.2 percent from Africans (L0, L1, L2, and L3), 46.6 percent from Amerindians (haplogroups A, B, C and D) and a small European contribution of 1.3 percent. These results indicated high genetic diversity in the Amerindian and African lineage groups, suggesting that the Brazilian Amazonian African-descendant populations reflect a possible population amalgamation of Amerindian women from different Amazonian indigenous tribes and African women from different geographic regions of Africa who had been brought to Brazil as slaves. The present study partially mapped the historical biological and social interactions that had occurred during the formation and expansion of Amazonian African-descendant communities.
Assuntos
Humanos , Masculino , Feminino , DNA Mitocondrial , Genética Populacional , África/etnologia , Brasil/etnologia , Variação Genética , População Negra/genética , Indígenas Sul-Americanos , Polimorfismo GenéticoRESUMO
The analysis of genetic variation in the nucleotide sequences of mitochondrial DNA, provides unique information about the population diversity and human identification. In this study, the mitochondrial DNA sequences of the first hypervariable region (HV-I) were analyzed in 243 unrelated individuals of seven Afro-descendents populations of the Amazon Region. Sequence polymorphisms were detected using PCR and direct sequencing analysis. A total of 133 different haplotypes were found determined by 97 variable nucleotides. Each one of the three more frequent haplotypes was shared by 9 samples and 91 sequences were unique. The genetic diversity was estimated to 0.9898+/-0.0016 and the probability of two random individuals showed identical mitochondrial DNA (mtDNA) haplotypes were 1.2%.
Assuntos
População Negra/genética , Regiões Determinantes de Complementaridade/genética , DNA Mitocondrial/genética , Variação Genética , Genética Populacional , Brasil , Impressões Digitais de DNA , Haplótipos , Humanos , Masculino , Reação em Cadeia da PolimeraseRESUMO
The analysis of genetic variation in the nucleotide sequences of mitochondrial DNA has been used as a tool in the study of history of different human populations, as Amerindians, Afro-descendents populations and furthermore admixed populations. In this study, the mitochondrial DNA was analyzed in 158 unrelated individuals in an admixed population of the Amazonian Region: Santarém-PA-Brazil. The polymorphisms were detected using both levels, analysis of restriction enzyme and direct sequencing. We observed a total of 49 different haplotypes were found determined by 46 variable nucleotides. The more frequent haplotypes (Hap03) was shared by five samples and 43 sequences were unique. The genetic diversity was estimated to 0.989+/-0.0067 and the probability of two random individuals showed identical mitochondrial DNA (mtDNA) haplotypes were 2.8%.
Assuntos
Regiões Determinantes de Complementaridade/genética , DNA Mitocondrial/genética , Genética Populacional , Polimorfismo Genético , Brasil , Impressões Digitais de DNA , Haplótipos , Humanos , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
The genetic consequences of the social policy of the past in relation to the formation of Afro-Brazilian societies are interesting and have been studied at various biological levels (classical polymorphisms and the mitochondrial and nuclear levels. These allow the estimation of the contribution of African genes and the participation of other ethnic groups in the formation of these communities. With this objective, uniparental systems of exclusively maternal (mtDNA) or paternal (Y-DNA) inheritance in the Curiaú community were analyzed. The results demonstrate a differential contribution of the maternal and paternal genetic systems. Thirty-three sequences were identified by mtDNA analysis; 53% showing an African and 47% an Amerindian origin. For the paternal system, 57% were of African, 37% of European, and 6% of Amerindian origin.
