Desenvolvimento e validação de sistema multiplex X-STR para identificação humana por DNA

• Autor(a) principal: Aquino, Juliana Gozi de
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/8702
• topic: X-STR; Multiplex; PCR; Human identification; X-STR; Multiplex; PCR; Identificação humana; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::BIOLOGIA MOLECULAR

New molecular analysis technologies used to evolving clinic and population studies of biodiversity and forensic identification have been developed based on microsatellite markers or STR Short Tandem Repeats . These STR markers, which are widely spread on genomes and characterized by their high degree of polymorphism, can be analyzed by PCR (Polymerase Chain Reaction) amplification technology. This analysis was facilitated from the development of simultaneous amplification system of multiples STR (multiplex STR) and automatic detection of amplification products by fluorescence. Lately, the use of STR markers of chromosome X (X-STR) has become significant in forensic practice. Due to their transmission ways, X-STR are useful at especial kinship investigation, showing advantages in relation to the use of STR autosomal. This study main focus was the development and validation of the multiplex system called LDD (X-STR) Decaplex, which was able to amplify ten X-STR loci (DXS7133, DXS7424, DXS8378, DXS6807, DXS7132, DXS10074, DXS7423, DXS8377, GATA172D05 and DXS10101) in order to be used in population genetics application, identification and forensic analysis. By using LDD (X-STR) Decaplex 170, individuals, who were self-appointed Africandescendants and genetically unrelated, were genotyped. Allele and genotype frequencies have not shown Hardy-Weinberg equilibrium deviation and are in agreement with the ones observed in other studies. The observed haplotypes were unique in male individual samples. The linkage disequilibrium analysis has not shown any association among the X-STR markers. The genetic diversity was high, ranging from 0.6218 (DXS7133 locus) to 0.9327 (DXS8377 locus). The parameters of Probability of Relatedness (PR), Avuncular Index (AI), Power of Exclusion (PE), Power of Discrimination and Likelihood Ratios were also high, showing that these ten X-STRs are highly polymorphous and discriminating on the studied population. The minimum DNA concentration for the amplification of the LDD (X-STR) Decaplex loci is 0.5 ng and it was also verified that the PCR amplification can be affected when more than 5 ng of DNA are added to the reactions. The "stutter" bands percentages were high to DXS7132 and DXS8377 loci. At the reproducing test, consistency among typing of different biological samples was observed, including the ones from remains. At the mixing test, the limit proportion in which two biological species coexisted was 2.5:1 ng (female-male). The results point out that LDD (X-STR) Decaplex loci are able to provide many important piece of information which, as a whole, are a very important tool at human identification and of kinship studies.