Ethnic categorization of the Brazilian population samples — Native Americans, European descendants,Mulattoes, and African descendants — using allelicfrequencies distribution of gene variants associatedwith neurodegenerative diseasesulattoes, and African descendants — using allelic frequencies distribution of gene variants associated with neurodegenerative diseases.
DOI:
https://doi.org/10.4238/wjehkt19Keywords:
Population Genetics, Brazil, Admixed Populations, SNPsAbstract
Three ancestral components — Native American, European, and African — comprise the Brazilian population, resulting in a high genetic diversity and distribution of polymorphism frequency. Therefore, a population study is necessary before analyzing disease-associated variants. Several genes previously described are associated with neurodegenerative diseases and their respective variants. However, the distribution of these gene variants has not been established in the heterogeneous Brazilian population. In this work, we analyzed polymorphic variants in samples of a
stratified Brazilian population to observe if there is any correlation between such heterogeneity and their respective ethnic and geographical origins. We selected individuals from Brazilian ethnic groups according to racial self-declaration: European descendants (N = 30), African descendants (N= 30), Mulattoes Brazilians (N = 30), as well as Native Americans (N =20), and individuals of Japanese descent (N = 30).
The study of PCA and other population parameters allowed the characterization of populations and
population groups. European descendant individuals were indistinguishable from Mulattoes (Fst = 0.001); on the other hand, the group of European descendant and Mulatto individuals indicated a moderate genetic differentiation from the European population (Fst = 0.102). The analyses showed that Native Americans (NAT) are a distinct group with moderate to significant differentiation from other population groups. We showed that the genotypic distributions of markers associated with neurodegenerative diseases vary in our populations. Thus, the interpretation of the associated
genotypes should consider the genetic composition of this population.
