Genomic ancestry of a sample population from the state of São Paulo, Brazil

Abstract

Allelic frequencies of eight autosomal short-tandem repeat (STR) loci (TH01, TPOx, CSF1PO, vWA, FES/FPS, F13A1, F13B, and CD4) were determined in 400 individuals born in the State of São Paulo. No significant deviations from Hardy-Weinberg equilibrium were found in any loci analyzed. The Unweighted Pair-Group Method with Arithmetic Mean (UPGMA) tree constructed based on genetic distances revealed that the present population was grouped with Europeans, and separated from African and Amerindian populations. Estimates of admixture components based on the gene identity method revealed 79% European, 14% African, and 7% Amerindian contributions to this Brazilian population sample.

Genomic ancestry in urban Afro-Brazilians

“…According to their skin pigmentation intensities, which was visually determined by a single evaluator, individuals were classified as Euro-Brazilians [object of a previous publication (Ferreira et al 2006)], mulattoes (n ¼ 150) and Afro-Brazilians (n ¼ 70). No other information, such as morphological features or ancestry, was considered for this classification, which, in these individuals, is positively correlated with their self-definition classification.…”

“…A previous ethnic admixture study (Ferreira et al 2006), based on autosomal short tandem repeat (STR) loci in a sample of white inhabitants from São Paulo State, estimated European, African and Amerindian contributions of 79%, 14% and 7%, respectively. In order to exhaustively explore the genetic variability and admixture landscapes that characterize the urban population of the São Paulo State and to conclude our previous report (Ferreira et al 2006), the ethnic compositions of two samples, mulattoes and Afro-Brazilians (defined according to the intensity of their skin pigmentation) from the same region were determined.…”

“…In order to exhaustively explore the genetic variability and admixture landscapes that characterize the urban population of the São Paulo State and to conclude our previous report (Ferreira et al 2006), the ethnic compositions of two samples, mulattoes and Afro-Brazilians (defined according to the intensity of their skin pigmentation) from the same region were determined.…”

Ocorrência familial e associação de polimorfismos dos genes H19 e IGF2 com as Síndromes Hipertensivas Gestacionais

“…Ferreira et al (2006), em estudo realizado com 400 pessoas nascidas no estado de São Paulo e identificadas como "brancas" nos prontuários médicos do HCFMRP-USP, estimaram que 79% da ancestralidade genética destes indivíduos era européia, 14% africana e 7% ameríndia. Esta grande ancestralidade africana na população considerada "branca" pode explicar os resultados encontrados no presente trabalho, que não mostrou relação da "cor da pele preta" com as síndromes hipertensivas gestacionais.…”

Relationship between Ancestry Inferred By Molecular Analysis, Self-Report and Hetero-Classification

“…While the grouping of individuals based on self-reported ancestry is a typical procedure for determining philogeographic groups in studies of the Brazilian population, the recent utilization of molecular markers for inferring genetic ancestry has revealed great genetic heterogeneity [16][17][18][19][20][21][22]. One of the problems of conducting association studies in miscegenated populations by using only self-reported ancestry or skin color as equivalents of ethnicity is the possibility of a spurious association with false-positive or false-negative results [23][24][25][26][27][28][29].…”