Avaliação de diferentes conjuntos de marcadores do cromossomo X na população residente do estado de São Paulo
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Data
2021-11-24
Autores
Januario, Bianca Belon
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Nas últimas décadas com o avanço da biotecnologia foi possível analisar os polimorfismos genéticos, os quais acabaram tornando-se uma importante ferramenta na identificação de pessoas. Na identificação humana as análises são baseadas no perfil genético de um indivíduo, por meio da utilização de marcadores como os STRs autossômicos, que são os mais utilizados em identificação humana como em análises de paternidade. Além dos STRs autossômicos, os STRs dos cromossomos sexuais podem ser utilizados para auxiliar na identificação quando há amostras degradadas ou em casos complexos de análise de parentesco. Outros marcadores são utilizados em identificação humana como os polimorfismos de inserção e deleção (InDels) e os polimorfismos de base única SNPs (single nucleotide polymorphisms). O foco desta pesquisa são os marcadores do cromossomo X, pois possuem características únicas, como seu padrão de herança e recombinação. Estes aspectos peculiares fazem com que sua análise seja importante na área forense. Neste trabalho foram analisadas amostras da população residente no estado de São Paulo, sendo 141 trios (pai, mãe e filha) dos quais foram avaliados os marcadores X-STRs presentes nos conjuntos de marcadores do Decaplex (10 X- STRs - Gusmão, 2009) e no kit comercial Investigator® Argus X-12QS (Qiagen). Os resultados mostraram que ambos os conjuntos são polimórficos para a população estudada, alcançando valores significativos de diversidade gênica: no Decaplex os marcadores GATA172D05 (0,83118) e DXS6809 (0,82181) apresentaram-se com valores mais altos de diversidade. Já nos 12 marcadores do Argus destacando o grupo de ligação 1 (LG1) obtendo o maior valor de diversidade haplotípica, 0,99835. Na análise do equilíbrio de Hardy-Weinberg nenhum marcador dos dois conjuntos analisados apresentou desvio significativo, nem estratificação populacional. No que se refere ao desequilíbrio de ligação houve associação entre marcadores de grupos de ligação diferentes na análise dos 12-XSTRs do kit Argus, DXS10134 – DXS10135. Entretanto, no conjunto de marcadores de 10 X-STRs – Decaplex não foi observado desequilíbrio de ligação. Os dois conjuntos de marcadores quando utilizados para análise de parentesco mostraram-se eficiente com valores expressivos de LR (likehood ratio) principalmente na análise de vínculo biológico entre supostas avó-neta. Os valores obtidos de LR com o Decaplex foi de 3,2160E+09 e com o Argus de 7,3840E+03. Portanto, os resultados obtidos neste trabalho levam a conclusão que os marcadores X-STRs testados são informativos e interessantes para análises de populações humanas e aplicáveis na genética forense.
In recent decades, with biotechnology advances it was possible to analyze genetic polymorphisms, which ended up becoming an important tool for identifying people. In human identification (HID) analyzes are based on individual genetic profile using markers such as autosomal STRs, the most used in human identification and paternity analyses. In addition to autosomal STRs analyses, sex chromosome STRs can be used to help identification with degraded samples or in complex cases of kinship analysis. Other markers are used in human identification such as insertion and deletion polymorphisms (InDels) and single nucleotide polymorphisms (SNPs). This research focuses in X chromosome markers because they have unique characteristics such as their pattern of inheritance and recombination. These peculiar aspects make analysis with these markers interesting in forensic area. In this work, samples from population residing in São Paulo state were analyzed, X-STRs markers present in the Decaplex marker sets (Gusmão, 2009) and in the Investigator® Argus commercial kit X-12QS (Qiagen) were used to genotyping 141 trios (father, mother and daughter). Results showed that both are polymorphic for the studied population reaching gene diversity significant values, Decaplex best markers were GATA172D05 (0.83118) and DXS6809 (0.82181) reaching higher values. Already in haplotypic diversity the 12 Argus markers highlighting the linkage group 1 (LG1) obtaining the highest value, 0.99835. In Hardy-Weinberg equilibrium analysis, none markers of the two analyzed sets presented significant deviation, nor population stratification. Regarding linkage disequilibrium, there was an association between markers from different linkage groups in 12-XSTRs of argus kit analysis, DXS10134 – DXS10135. However, in 10 X-STRs markers – Decaplex was not observed linkage disequilibrium. The two sets of markers when used for kinship analysis are efficient based on expressive values of LR (likehood ratio) mainly in kinship analysis between supposed grandmother-grandchildren. The LR values obtained with the Decaplex were 3.2160E+09 and with Argus were 7.3840E+03. Therefore, the results obtained in this work lead to the conclusion that the tested X-STRs markers are informative and interesting for the analysis of human populations and applicable in forensic genetics.
In recent decades, with biotechnology advances it was possible to analyze genetic polymorphisms, which ended up becoming an important tool for identifying people. In human identification (HID) analyzes are based on individual genetic profile using markers such as autosomal STRs, the most used in human identification and paternity analyses. In addition to autosomal STRs analyses, sex chromosome STRs can be used to help identification with degraded samples or in complex cases of kinship analysis. Other markers are used in human identification such as insertion and deletion polymorphisms (InDels) and single nucleotide polymorphisms (SNPs). This research focuses in X chromosome markers because they have unique characteristics such as their pattern of inheritance and recombination. These peculiar aspects make analysis with these markers interesting in forensic area. In this work, samples from population residing in São Paulo state were analyzed, X-STRs markers present in the Decaplex marker sets (Gusmão, 2009) and in the Investigator® Argus commercial kit X-12QS (Qiagen) were used to genotyping 141 trios (father, mother and daughter). Results showed that both are polymorphic for the studied population reaching gene diversity significant values, Decaplex best markers were GATA172D05 (0.83118) and DXS6809 (0.82181) reaching higher values. Already in haplotypic diversity the 12 Argus markers highlighting the linkage group 1 (LG1) obtaining the highest value, 0.99835. In Hardy-Weinberg equilibrium analysis, none markers of the two analyzed sets presented significant deviation, nor population stratification. Regarding linkage disequilibrium, there was an association between markers from different linkage groups in 12-XSTRs of argus kit analysis, DXS10134 – DXS10135. However, in 10 X-STRs markers – Decaplex was not observed linkage disequilibrium. The two sets of markers when used for kinship analysis are efficient based on expressive values of LR (likehood ratio) mainly in kinship analysis between supposed grandmother-grandchildren. The LR values obtained with the Decaplex were 3.2160E+09 and with Argus were 7.3840E+03. Therefore, the results obtained in this work lead to the conclusion that the tested X-STRs markers are informative and interesting for the analysis of human populations and applicable in forensic genetics.
Descrição
Palavras-chave
Cromossomo X, Genética forense, Identificação humana, São Paulo, X-STRs, Forensic genetics, Human identification, X chromosome