Molecular variabilite in Y cromosome in quilombo remnants in Vale do Ribeira / "Variabilidade molecular do cromossomo Y em remanescentes de quilombos do Vale do Ribeira"

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Abstract At least 25 quilombos remnants are supposed to exist in the Vale do Ribeira region, located in the southern part of São Paulo State. Thirteen of those quilombo remnants have already been identified and officially recognized. In order to understand the structure and history of the foundation of these quilombo remnants, we studied male individuals belonging to six populations: Abobral Left Margin (48 individuals), Galvão (22), São Pedro (22), Pedro Cubas (60), Pilões (15) and Maria Rosa (9), in addition to 81 individuals sampled from the city of São Paulo, for four Y chromosome polymorphic loci: two microsatellite loci (DYS19 and DYS390), one SNP (DYS199) and one Alu insertion (YAP). The genotypes were identified by DNA amplification by polymerase chain reaction (PCR) followed by acrylamide gel electrophoresis. A fifth locus was also analysed, by a different SNP (M168), but only in a few individuals. In this analysis DNA direct sequencing was employed. The allelic frequencies in the locus DYS19 indicated significant male Portuguese contribution in the quilombos. The Amerindian specific allele (T) of the DYS199 locus indicated little or no contribution from Amerindian males, except the population of Pedro Cubas. The Alu insertion (YAP or DYS287), frequent in Africans, is a good indicator of African ancestry, although not all Africans show it. Thus, the analysis of the M168 locus helped to determine the origin of Y chromosomes. These markers indicated a range from 11 to 55% of probable African contribution in the quilombos. Only in Pedro Cubas the frequency of African Y chromosomes was higher than the one European Y chromosomes. In Abobral, the frequency of African Y chromosomes was approximately 40%, being the most African of the quilombo populations, when Y chromosomes are considered. The total haplotype diversity in the quilombos was similar to the one observed for the sample from São Paulo, probably due to the diversity of African populatons that originated the quilombos, or the admixture with other ethnic groups. Galvão showed the lowest diversity, indicating that this population was the most influenced by founder effects. In the neighbor-joining tree built with allelic frequencies obtained in the quilombos, São Paulo and other populations previously reported, the quilombos of Galvão, São Pedro and Abobral were closer to the African populations and Pedro Cubas is the only one close to Amerindians. Pilões and Maria Rosa were closer to São Paulo, white Brazilians and Portuguese populations, indicating European contribution.

ASSUNTO(S)

cromosome y genetic population genética humana vale do ribeira quilombo genética de populações human genetic quilombo cromossomo y

ACESSO AO ARTIGO

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