RESUMO
This work was undertaken to ascertain to what degree the physical appearance of a Brazilian individual was predictive of genomic African ancestry. Using a panel of 10 population-specific alleles, we assigned to each person an African ancestry index (AAI). The procedure was able to tell apart, with no overlaps, 20 males from northern Portugal from 20 males from São Tomé Island on the west coast of Africa. We also tested 10 Brazilian Amerindians and observed that their AAI values fell in the same range as the Europeans. Finally, we studied two different Brazilian population samples. The first consisted of 173 individuals from a rural Southeastern community, clinically classified according to their Color (white, black, or intermediate) with a multivariate evaluation based on skin pigmentation in the medial part of the arm, hair color and texture, and the shape of the nose and lips. In contrast to the clear-cut results with the African and European samples, our results showed large variances and extensive overlaps among the three Color categories. We next embarked on a study of 200 unrelated Brazilian white males who originated from cosmopolitan centers of the four major geographic regions of the country. The results showed AAI values intermediate between Europeans and Africans, even in southern Brazil, a region predominantly peopled by European immigrants. Our data suggest that in Brazil, at an individual level, color, as determined by physical evaluation, is a poor predictor of genomic African ancestry, estimated by molecular markers.
Assuntos
População Negra/genética , DNA Mitocondrial/genética , Pigmentação da Pele/genética , População Branca/genética , África/etnologia , Ilhas Atlânticas/etnologia , Brasil , Geografia , Humanos , Indígenas Sul-Americanos/genética , PortugalRESUMO
Panaquire is a population in Venezuela founded in 1733 by Spaniards from the Canary Islands. In order to define the genetic characteristics of this population the following loci were studied: ABO, RH (Cc, D, Ee), FY, K, JK, HB, ESD, ACP1, HP, TF, CP and ALB. Its sociohistorical features were also investigated. Historic censuses reveal that ethnically Blacks were the most important group in this village during the year 1800 (76%), followed by Amerindians (9%), Mulattoes (5%) and Whites (7%). The results of this analysis show that presently the most important genetic component is of African origin (59%), followed by Amerindian (26%) and Caucasian (15%) contributions. These results suggest that Canarians founded Panaquire, but unfavorable sociopolitical and environmental circumstances, as well as the entrance of former slaves, determined the village's evolution as a Black population. Important gene flow also occurred from Indian settlements, and some admixture with Whites. Our analysis shows once again the importance of handling together genetic and sociocultural variables to have a better interpretation of the evolution of human populations.