title: Migration in Afro-Brazilian rural communities: crossing demographic and genetic data.
abstract: Many studies have used genetic markers to understand global migration patterns of our species. However, there are only few studies of human migration on a local scale. We, therefore, researched migration dynamics in three Afro-Brazilian rural communities, using demographic data and ten Ancestry Informative Markers. In addition to the description of migration and marriage structures, we carried out genetic comparisons between the three populations, as well as between locals and migrants from each community. Genetic admixture analyses were conducted according to the gene-identity method, with Sub-Saharan Africans, Amerindians, and Europeans as parental populations. The three analyzed Afro-Brazilian rural communities consisted of 16% to 30% of migrants, most of them women. The age pyramid revealed a gap in the segment of men aged between 20 to 30 yrs. While endogamous marriages predominated, exogamous marriages were mainly patrilocal. Migration dynamics are apparently associated with matrimonial customs and other social practices of such communities. The impact of migration upon the populations' genetic composition was low but showed an increase in European alleles with a concomitant decrease in the Amerindian contribution. Admixture analysis evidenced a higher African contribution to the gene pool of the studied populations, followed by the contribution of Europeans and Amerindians, respectively.
authors.affiliation: Departamento de Genética e Morfologia, Instituto de Ciências Biológicas, Universidade de Brasilia, Brasilia, DF, Brazil. guerraamorim@gmail.com
authors.forename: Carlos Eduardo G
authors.initials: CE
authors.lastname: Amorim
authors.forename: Carolina C
authors.initials: CC
authors.lastname: Gontijo
authors.forename: Gabriel
authors.initials: G
authors.lastname: Falcão-Alencar
authors.forename: Neide M O
authors.initials: NM
authors.lastname: Godinho
authors.forename: Rafaela C P
authors.initials: RC
authors.lastname: Toledo
authors.forename: Maria Angélica F
authors.initials: MA
authors.lastname: Pedrosa
authors.forename: Marcelo R
authors.initials: MR
authors.lastname: Luizon
authors.forename: Aguinaldo L
authors.initials: AL
authors.lastname: Simões
authors.forename: Maria N
authors.initials: MN
authors.lastname: Klautau-Guimãres
authors.forename: Silviene F
authors.initials: SF
authors.lastname: Oliveira
mesh_terms: D000328:Adult; D044466:Asian People; D044383:Black People; D001938:Brazil; D003241:Consanguinity; D004641:Emigration and Immigration / Q000706:statistics & numerical data*; D005260:Female; D051456:Gene Flow / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D008297:Male; D008393:Marriage / Q000706:statistics & numerical data*; D008957:Models, Genetic; D012424:Rural Population / Q000706:statistics & numerical data*; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D044465:White People; D055815:Young Adult