title: Genomic ancestry of rural African-derived populations from Southeastern Brazil.
abstract: OBJECTIVE
  xMany Africans were brought to Brazil as slaves. The runaway or abandoned slaves founded isolated communities named quilombos. There are many quilombo remnants in Vale do Ribeira region in the southern part of São Paulo State. The aim of our study was to contribute to understanding the origins of these populations, through admixture studies.
  
  
  METHODS
  We genotyped 307 unrelated DNA samples obtained from ten quilombo populations from Vale do Ribeira region, using a panel of 48 INDEL polymorphisms. We estimated genetic differentiation between populations (F(ST) ) and genomic ancestry from these populations. Our data were compared to a similar study performed in quilombo remnants from the Brazilian Amazon region.
  
  
  RESULTS
  Population admixture estimates showed high degree of miscegenation in the quilombo remnants from Vale do Ribeira (average admixture estimates at 39.7% of African, 39.0% of European and 21.3% of Amerindian contribution). The proportions of ancestral genes varied greatly among individuals, ranging from 7.3 to 69.5%, 12.9 to 68.3%, and 7.3 to 58.5% (African, European, and Amerindian, respectively). Genetic differentiation between these populations was low (all F(ST) values <5%), indicating gene flow between them. Both groups of quilombos, from Vale do Ribeira and Amazon, presented similar patterns of admixture.
  
  
  CONCLUSIONS
  INDEL markers were useful to evidence the triple interbreeding among African, European, and Amerindian in the formation of quilombo populations. The low F(ST) values suggested gene flow among quilombos from Vale do Ribeira. Our data highlight the important role of Amerindians in the formation of quilombo populations.
authors.affiliation: Centro de Estudos do Genoma Humano, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Lilian
authors.initials: L
authors.lastname: Kimura
authors.forename: Elzemar Martins
authors.initials: EM
authors.lastname: Ribeiro-Rodrigues
authors.forename: Maria Teresa Balester
authors.initials: MT
authors.lastname: De Mello Auricchio
authors.forename: João Pedro
authors.initials: JP
authors.lastname: Vicente
authors.forename: Sidney Emanuel
authors.initials: SE
authors.lastname: Batista Santos
authors.forename: Regina Célia
authors.initials: RC
authors.lastname: Mingroni-Netto
mesh_terms: D044383:Black People / Q000235:genetics*; D001938:Brazil; D001947:Breeding; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D023281:Genomics; D005838:Genotype; D006801:Humans; D054643:INDEL Mutation; D007199:Indians, South American / Q000235:genetics; D008297:Male; D017422:Sequence Analysis, DNA; D044465:White People / Q000235:genetics