title: Amazonian Amerindians exhibit high variability of KIR profiles.
abstract: Natural killer cell immunoglobulin-like receptors (KIRs) mediate cell lysis through the recognition of human leukocyte antigen class I complexes in target cells, playing an important role in innate immune response. In this context, disease-based selective pressures could be relevant, leaving signatures detected by population studies. However, most population studies on KIR variability have focused on Europe and Asia, while Americas, Oceania, and Africa remain poorly studied. The aim of this study was to analyze the variability of KIR genes in Amerindian tribes from the Amazon region to infer about their evolutionary history. KIR profiles were estimated in 40 individuals from six Amazonian Amerindian tribes using single specific primer polymerase chain reaction. Twenty-five different profiles were identified, and surprisingly, the haplogroup A frequency was the lowest observed in human populations (16%). Results showed also that KIR variability was higher in this group in contrast to Venezuelan Amerindians. Principal components analysis evidenced that Amerindians formed a separated group from other worldwide populations and showed a higher intraethnic differentiation in comparison to other ethnic groups. Such pattern may reflect small effective size and intense genetic drift. However, because of the role of KIR in immune response, selective pressures cannot be entirely ruled out.
authors.affiliation: Laboratório de Genética Humana e Médica, Departamento de Patologia, Centro de Ciências Biológicas, Universidade Federal do Pará, Caixa Postal 8615, 66075-900 Belém, Pará, Brazil.
authors.forename: Paloma Daguer
authors.initials: PD
authors.lastname: Ewerton
authors.forename: Mauro de Meira
authors.initials: Mde M
authors.lastname: Leite
authors.forename: Milena
authors.initials: M
authors.lastname: Magalhães
authors.forename: Leonardo
authors.initials: L
authors.lastname: Sena
authors.forename: Eduardo José
authors.initials: EJ
authors.lastname: Melo dos Santos
mesh_terms: D001938:Brazil; D019143:Evolution, Molecular; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D007199:Indians, South American / Q000235:genetics*; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics*; D025341:Principal Component Analysis; D014687:Venezuela
chemical_list: C490245:GEM protein, human; D020559:Monomeric GTP-Binding Proteins