Caracterização genética da população do Estado do Mato Grosso e do Distrito Federal (Brasília) pela análise de 32 polimorfismos de inserção/deleção (InDels) no cromossomo X
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Data
2018-04-26
Autores
Polverari, Fernanda Silva [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A análise dos polimorfismos do DNA é a melhor ferramenta encontrada para resolução de casos de identificação humana, sendo os marcadores STRs (short tandem repeat) localizados em regiões autossômicas os principais e mais utilizados para esta finalidade. Apesar da indiscutível reprodutibilidade destes marcadores, quando são analisados em amostras degradadas podem não apresentar bons resultados, o que dificulta a resolução dos casos. Assim, há a necessidade de uma alternativa e, atualmente, a mais indicada é a utilização dos polimorfismos bialélicos. A análise do cromossomo sexual X também vem ganhando importância significativa no contexto forense, devido ao seu padrão de transmissão entre os genitores. Neste trabalho, caracterizamos as populações brasileiras do estado do Mato Grosso e do Distrito Federal pela análise de 32 polimorfismos de inserção/deleção no cromossomo X (X-InDels), tendo em vista que os dados destes polimorfismos nestas populações são ainda inéditos, e para que esses marcadores também possam no futuro auxiliar a resolução de casos forenses em nosso país. Para identificar a diversidade genética foram analisados os perfis genotípicos de 303 indivíduos não aparentados nascidos no estado do Mato Grosso e 179 indivíduos não aparentados e residentes em Brasília. Os resultados indicam que o painel dos 32 X-Indels é bastante eficiente para a sua finalidade, sendo que praticamente todos os marcadores se mostraram altamente informativos para as populações estudadas. O teste de equilíbrio de HardyWeinberg foi realizado nas amostras femininas de ambas as populações e não foram verificados desvios significativos. O painel demonstrou alta eficiência forense, confirmado pelo alto poder de discriminação para Mato Grosso (PDF=0,999999999997 e PDM=0,99999997) e para Brasília ((PDF=0,999999999998 e PDM=0,99999998), e pelo elevado poder de exclusão observado em trios: suposto pai/mãe/filha (0,999998/Mato Grosso e 0,999997/Brasília) e duos: suposto pai/filha (0,9996/Mato Grosso e 0,9995/Brasília). No estudo comparativo com outras populações, Mato Grosso e Brasília estão mais próximos ao estado de São Paulo, à três departamentos colombianos e às populações europeias. A proporção de ancestralidade confirmou a miscigenação das populações estudadas, sendo identificado uma contribuição praticamente equilibrada para europeus, africanos e nativo-americanos. Conclui-se que o conhecimento acerca dos marcadores de inserção/deleção no cromossomo X pode ser ampliado, uma vez que na literatura ainda há pouco material disponível sobre o assunto; entretanto os dados deste trabalho já demonstram seu potencial como método complementar para a análise de amostras forenses, pois foram identificados elevados valores de poder de discriminação e exclusão
The analysis of DNA polymorphisms is the best tool found for solving cases of human identification, and the Short Tandem Repeat (STR) markers used in the autosomal regions are the main and most marker used for this purpose. Despite the undeniable reproducibility of these markers, when analyzed in degraded samples they may not present good results, which makes it difficult to solve the cases. Because of this, there is a need for an alternative tool and currently the most indicated is the use of the biallelic polymorphisms. In this way, the analysis of the sex chromosome X has gained significant importance in the forensic context, due to its pattern of transmission between the parents. In this work, we characterize the Brazilian populations of the state of Mato Grosso and the Federal District by the analysis of 32 insertion/deletion polymorphisms on the X chromosome (X-InDels), considering that the data of this polymorphism in these populations are still unpublished, and for that these markers may also in the future help the resolution of forensic cases in our country. To identify the genetic diversity, the genotypic profiles of 303 unrelated individuals born in the state of Mato Grosso and 179 unrelated individuals living in Brasília were analyzed. The results shows that the 32 X-Indels panel is very efficient to its purpose, being almost all markers highly informative for the studied populations. The Hardy-Weinberg equilibrium test was performed on the female samples from both populations and no significant deviations were observed. The panel demonstrated high forensic efficiency, confirmed by the high discriminatory power for Mato Grosso (PDF= 0.9999999999997 and PDM=0.999999997) and Brasília (PDF=0.9999999999998 and PDM=0.999999998), and by the high exclusion power observed in trios: supposed father/mother/daughter (0.999998/Mato Grosso and 0,999997/Brasília) and duos: supposed father/daughter (0.9996/Mato Grosso and 0,9995/Brasília). In the comparative study with other populations, Mato Grosso and Brasília are closer to the state of São Paulo, to three departments in Colombia and to European populations. The proportion of ancestry confirmed the admixture of the populations studied, with a practically balanced contribution being identified for Europeans, Africans and American natives. We could concluded that knowledge about insertion/deletion markers on the X chromosome can be amplified, since in the literature there is still fewer available material on the subject, however the data of this work already demonstrates its potential as a complementary method for the analysis of forensic samples, since were identified high values of power of discrimination and exclusion.
The analysis of DNA polymorphisms is the best tool found for solving cases of human identification, and the Short Tandem Repeat (STR) markers used in the autosomal regions are the main and most marker used for this purpose. Despite the undeniable reproducibility of these markers, when analyzed in degraded samples they may not present good results, which makes it difficult to solve the cases. Because of this, there is a need for an alternative tool and currently the most indicated is the use of the biallelic polymorphisms. In this way, the analysis of the sex chromosome X has gained significant importance in the forensic context, due to its pattern of transmission between the parents. In this work, we characterize the Brazilian populations of the state of Mato Grosso and the Federal District by the analysis of 32 insertion/deletion polymorphisms on the X chromosome (X-InDels), considering that the data of this polymorphism in these populations are still unpublished, and for that these markers may also in the future help the resolution of forensic cases in our country. To identify the genetic diversity, the genotypic profiles of 303 unrelated individuals born in the state of Mato Grosso and 179 unrelated individuals living in Brasília were analyzed. The results shows that the 32 X-Indels panel is very efficient to its purpose, being almost all markers highly informative for the studied populations. The Hardy-Weinberg equilibrium test was performed on the female samples from both populations and no significant deviations were observed. The panel demonstrated high forensic efficiency, confirmed by the high discriminatory power for Mato Grosso (PDF= 0.9999999999997 and PDM=0.999999997) and Brasília (PDF=0.9999999999998 and PDM=0.999999998), and by the high exclusion power observed in trios: supposed father/mother/daughter (0.999998/Mato Grosso and 0,999997/Brasília) and duos: supposed father/daughter (0.9996/Mato Grosso and 0,9995/Brasília). In the comparative study with other populations, Mato Grosso and Brasília are closer to the state of São Paulo, to three departments in Colombia and to European populations. The proportion of ancestry confirmed the admixture of the populations studied, with a practically balanced contribution being identified for Europeans, Africans and American natives. We could concluded that knowledge about insertion/deletion markers on the X chromosome can be amplified, since in the literature there is still fewer available material on the subject, however the data of this work already demonstrates its potential as a complementary method for the analysis of forensic samples, since were identified high values of power of discrimination and exclusion.
Descrição
Palavras-chave
Identificação humana, Genética populacional, Polimorfismos de inserção/deleção, InDels, Cromossomo X, X-Indels, Mato Grosso, Brasília, Brasil, Human identification, Population genetics, Insertion/deletion polymorphism, InDels, X chromosome, X-InDels, Mato Grosso, Brasília, Brazil