DNA mitocondrial como ferramenta na investigação da ancestralidade materna e da estrutura populacional no Espírito Santo

Abstract

In addition to its valuable utility in forensic investigations, mitochondrial DNA (mtDNA) analysis is a reliable tool to uncover the origins of admixed populations, such as Brazilians. The state of Espírito Santo (ES), similar to other coastal Brazilian states, has a population shaped by 3 main ancestral roots: Amerindian, African and European. Among the latter, the Pomeranian descendants stand out due to the preservation of the traditional aspects of their culture, especially the Pomeranian language. Although the mitochondrial genetic diversity in ES has been investigated by an earlier study, the available database presents reduced sample size (N = 97) whose ethnic composition, geographical origin and territorial coverage are unknown. To increase the knowledge of maternal ancestry and to investigate the population’s genetic stratification, complete control region data were produced for the general (N=214) and Pomeranian (N=77) groups, totaling 291 haplotypes. The sampling of the general population included individuals from the 4 macroregions of the ES, namely Metropolitan (N = 81), South (N = 62), Central (N = 54) and North (N = 17). Regarding the general population, the high values of haplotype diversity (H=99.9%) and pairwise differences (MNPD=16.9) found are in agreement with those reported for other populations in the southeast region of the country. Regarding maternal inheritance, the ES populations stood out due to the predominance of European haplogroups (49.1%), although the North macroregion had a higher African profile (47.1%). Although not statistically significant, analyses of genetic distances indicated a genetic stratification of the general population, which would compromise the adoption of a single forensic database of mtDNA lineages for all ES. Among the Pomeranians, the lowest MNPD value (11.2) and the high percentage of shared haplotypes (15%) were indicative of founder events. The FST analysis showed that the Pomeranians (98.7% of European lineages) are genetically isolated from the other admixed populations in Brazil. This study demonstrated that the ES state contains singularities regarding the intrapopulational and interpopulational diversity of mtDNA. Even after 5 centuries of interethnic admixture, the present-day population of Espírito Santo harbors genetic marks that trace back to the historical aspects of its formation.