Marcadores do cromossomo Y no estudo de linhagens paternas da população brasileira

• Autor(a) principal: Rêgo, Juliana Jannuzzi Duclos do
• 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/1/16119
• topic: Y Chromosome; Y-STR markers; Y-SNP markers; Brazilian population; Cromossomo Y; Marcadores Y-STR; Marcadores Y-SNP; População brasileira; Genética de populações; Cromossomo Y; Brasil População; População Aspectos genéticos; CNPQ::CIENCIAS BIOLOGICAS::GENETICA

The Brazilian population is genetically very admixed, resulting from the mixture of three major genetic components from the European, African and Native-american continents. Genetic markers of the Y chromosome are powerful tools in the characterization of male lineages, since, about 95% of its extent (non-recombinant region of the Y chromosome or NRY), does not recombine with the X chromosome. The NRY portion is transmitted unchanged over generations as haplotype unless mutations occur. Y chromosome analysis is performed using Y-STR markers, which define haplotypes, or Y-SNP, which define haplogroups. Studies that aim to characterize Y-STR haplotypes in the Brazilian population have been performed, however, considering the high diversity within and between Brazilian regions, these do not represent in detail the Brazilian population dynamics. In addition, studies that aimed characterizing male lineages in Brazilian population samples are also scarce and have the same limitation, not representing all the existing population diversity. Thus, it seems to be relevant to deepen the knowledge of the genetic composition of the Brazilian population through the integrated analysis of a large number of Y-STR and Y-SNP loci in a large population sample. The molecular analysis of the Y chromosome of 1640 unrelated men from 12 states of the five geopolitical regions of Brazil was performed. The DNA of the samples was extracted by two methodologies: organic extraction with the use of phenol-chloroform/isoamyl alcohol and extraction with Chelex® resin. The Y-STR haplotypes were generated after PCR with the 26 markers of the commercial Yfiler® Plus kit, followed by electrophoresis in automatic sequencer ABI 3500. The haplogroup determination was done through 5 PCR multiplexes and 1 monoplex of 45 Y -SNPs, followed by the single base sequencing and electrophoresis in automatic sequencer ABI 3500. High haplotype diversities were found in Brazilian populations with the Yfiler® Plus kit, showing high intrapopulation discrimination and, therefore, this kit is very useful in the forensic context. The genetic distance analysis indicates that the Brazilian samples analyzed are very close, allowing its use as a single Brazilian database in forensic analysis. In total, 349 men from Rio de Janeiro, São Paulo and Maranhão were genotyped with Y-SNP markers. In all samples, the main haplogroups were the Europeans, followed by Africans, Asians and Native Americans. This corroborates historical data about the colonization of Brazilian territory by Europeans, since the main genetic component comes from the Iberian Peninsula. The analysis of the performance of the haplogroup prediction programs allows to conclude that, even with an accurace rate of 73.95%, these tools should be used with caution, only to assist Y-SNPs genotyping, and also, the Y-STR markers set used should be taken into account.