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Authors
Advisor(s)
Abstract(s)
A migração de indivíduos é um dos principais contribuidores para a introdução de
variabilidade genética dentro das populações. Nas últimas duas décadas em Portugal, mais
particularmente Lisboa, recebeu um grande número destes migrantes. A comunidade de
imigrantes brasileiros é uma das principais comunidades estrangeiras atualmente a residir em
Portugal, constituindo, em 2020, cerca de 184 000 indivíduos.
As características únicas do DNAmt, ao ser transmitido exclusivamente por via materna
e não sofrendo recombinação, fazem deste um marcador muito útil, tendo várias aplicações
como o estudo da evolução das populações, a utilização em perícias forenses e a genética
médica.
Neste estudo foi realizada a sequenciação de DNAmt de 75 imigrantes brasileiros a
residir em Lisboa, de modo a determinar o impacto que o pool genético desta população poderá
ter no gene pool da população lisboeta. Para isso foi amplificada a região controlo do DNAmt
com dois pares de primers L15971 / H016 e L16555 / H639. Os produtos amplificados foram
sequenciados com BigDye®Terminator v.3.1 Cycle Sequence (AB) e detetados no SeqStudio™
Genetic Analyzer (AB). Os resultados obtidos foram analisados nos softwares Sequencing
Analysis v7. e SeqScape v4. (AB), onde as sequências obtidas foram comparadas com a rCRS
obtendo haplótipos que, recorrendo à Phylotree, build 17, podem ser classificados em
haplogrupos. Sendo que a maioria dos haplótipos obtidos neste estudo não apresentaram
correspondência na base de dados EMPOP. Tratando-se de uma população extremamente
heterogénea, com cerca de metade dos haplótipos obtidos pertencendo ao macrohaplogrupo L,
característico de populações africanas, um quarto dos haplótipos correspondem a haplótipos sul
americanos, sendo o quarto restante pertencente a populações euroasiáticas.
Migration is one of the main factors for genetic variability within populations. Currently, the Portuguese population, and particularly the population from Lisbon, welcomes a considerable number of immigrants. Brazilian immigrants are the main foreign community in Portugal, with about 184 000 individuals in 2020. Mitochondrial DNA (mtDNA), due to its unique characteristics such as being exclusively maternal inheritance and suffering no recombination, which results in its slow evolution, is a useful genetic marker in various areas such as forensic the study the evolution of populations, forensic genetics and medical genetics. In this study mtDNA sequencing analysis of 75 Brazilian immigrants who currently live in Lisbon were carried out in order to assess the impact of this population on the Portuguese gene pool. The mtDNA control region were amplified using two pairs of primers - L15971 / H016 and L16555 / H639. The amplified products were then sequenced using BigDye®Terminator v.3.1 Cycle Sequence (AB) and detected in the SeqStudio™ Genetic Analyzer (AB). The results were analyzed with the Sequencing Analysis v7. and SeqScape v4. (AB) softwares, where the obtained sequences were compared with the rCRS in order to obtain haplotypes that, with Phylotree, build 17, can be converted in haplogroups. From our results, it is possible to confirm that this Brazilian population living in Lisbon presents a high number of unique haplotypes, most of them had no coincidence on EMPOP Forensic database. It´s an extremely heterogeneous population with half of the studied haplotypes belonging to macrohaplogroup L, characteristic mainly of Sub-Saharan region of Africa, and a quarter of the studied haplotypes belonging to South American population and the other quarter belonging to Euro Asiatic population.
Migration is one of the main factors for genetic variability within populations. Currently, the Portuguese population, and particularly the population from Lisbon, welcomes a considerable number of immigrants. Brazilian immigrants are the main foreign community in Portugal, with about 184 000 individuals in 2020. Mitochondrial DNA (mtDNA), due to its unique characteristics such as being exclusively maternal inheritance and suffering no recombination, which results in its slow evolution, is a useful genetic marker in various areas such as forensic the study the evolution of populations, forensic genetics and medical genetics. In this study mtDNA sequencing analysis of 75 Brazilian immigrants who currently live in Lisbon were carried out in order to assess the impact of this population on the Portuguese gene pool. The mtDNA control region were amplified using two pairs of primers - L15971 / H016 and L16555 / H639. The amplified products were then sequenced using BigDye®Terminator v.3.1 Cycle Sequence (AB) and detected in the SeqStudio™ Genetic Analyzer (AB). The results were analyzed with the Sequencing Analysis v7. and SeqScape v4. (AB) softwares, where the obtained sequences were compared with the rCRS in order to obtain haplotypes that, with Phylotree, build 17, can be converted in haplogroups. From our results, it is possible to confirm that this Brazilian population living in Lisbon presents a high number of unique haplotypes, most of them had no coincidence on EMPOP Forensic database. It´s an extremely heterogeneous population with half of the studied haplotypes belonging to macrohaplogroup L, characteristic mainly of Sub-Saharan region of Africa, and a quarter of the studied haplotypes belonging to South American population and the other quarter belonging to Euro Asiatic population.
Description
Tese de mestrado, Biologia Molecular e Genética, 2022, Universidade de Lisboa, Faculdade de Ciências
Keywords
DNAmt Região controlo total Brasil Teses de mestrado - 2023