title: Mitochondrial DNA variability among eight Tikúna villages: evidence for an intratribal genetic heterogeneity pattern.
abstract: To study the genetic structure of the Tikúna tribe, four major Native American mitochondrial DNA (mtDNA) founder haplogroups were analyzed in 187 Amerindians from eight Tikúna villages located in the Brazilian Amazon. The central position of these villages in the continent makes them relevant for attempts to reconstruct population movements in South America. In this geographic region, there is particular concern regarding the genetic structure of the Tikúna tribe, formerly designated "enigmatic" due to its remarkable degree of intratribal homogeneity and the scarcity of private protein variants. In spite of its large population size and geographic distribution, the Tikúna tribe presents marked genetic and linguistic isolation. All individuals presented indigenous mtDNA haplogroups. An intratribal genetic heterogeneity pattern characterized by two highly homogeneous Tikúna groups that differ considerably from each other was observed. Such a finding was unexpected, since the Tikúna tribe is characterized by a social system that favors intratribal exogamy and patrilocality that would lead to a higher female migration rate and homogenization of the mtDNA gene pool. Demographic explosions and religious events, which significantly changed the sizes and compositions of many Tikúna villages, may be reflected in the genetic results presented here.
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto-SP, Brazil. ctmendes@ffclrp.usp.br
authors.forename: Celso Teixeira
authors.initials: CT
authors.lastname: Mendes-Junior
authors.forename: Aguinaldo Luiz
authors.initials: AL
authors.lastname: Simões
mesh_terms: D001938:Brazil; D004272:DNA, Mitochondrial / Q000737:chemistry*; D005260:Female; D005819:Genetic Markers; D014644:Genetic Variation; D006801:Humans; D007199:Indians, South American / Q000235:genetics*; D008297:Male; D011157:Population Dynamics; D012919:Social Behavior; D012934:Social Isolation
chemical_list: D004272:DNA, Mitochondrial; D005819:Genetic Markers