title: Variability of innate immune system genes in Native American populations-relationship with history and epidemiology.
abstract: OBJECTIVE
  The immune system of a host, defending him/her against invading pathogens, has two main subsystems: innate immunity and acquired immunity. There are several evidences showing that Native American populations are immunologically different from non-Native populations. Our aim was to describe the variability of innate immune system genes in Native American populations.
  
  
  METHODS
  We investigated heterozygozities and patterns of population differentiation (FST ) of 14 polymorphisms related to the innate immune response in five Native American populations (Aché, Guarani-Kaiowá, Guarani-Ñandeva, Kaingang, and Xavante) and the results were compared with the three major world population data (YRI, CEU, and CHB) available at the 1,000 genomes database.
  
  
  RESULTS
  Mean heterozygosities ranged between 0.241 ± 0.057 (Aché) and 0.343 ± 0.033 (Kaingang), but no significant differences were observed (Friedman test, P = 0.197). Mean heterozygosities were also not significantly different when Amerindians were pooled and compared with the 1000 genomes populations (Friedman test, P = 0.506). When the Native American populations were grouped as Amerindians, a significantly higher FST value (0.194) was observed between the Amerindian and African populations. The Ewens-Watterson neutrality test showed that these markers are not under strong selective pressure.
  
  
  CONCLUSIONS
  Native American populations present similar levels of heterozygosity as those of other continents, but are different from Africans in the frequency of polymorphisms of innate immune genes. This higher differentiation is probably due to demographic processes that occurred during the out-of-Africa event.
authors.affiliation: Departamento De Genética, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.
authors.forename: Juliana Dal-Ri
authors.initials: JD
authors.lastname: Lindenau
authors.affiliation: Departamento De Genética, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.
authors.forename: Francisco Mauro
authors.initials: FM
authors.lastname: Salzano
authors.affiliation: School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-2402.
authors.forename: Ana Magdalena
authors.initials: AM
authors.lastname: Hurtado
authors.affiliation: School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-2402.
authors.forename: Kim R
authors.initials: KR
authors.lastname: Hill
authors.affiliation: Departamento De Genética, Universidade Federal Do Paraná, Curitiba, PR, Brazil.
authors.forename: Maria Luiza
authors.initials: ML
authors.lastname: Petzl-Erler
authors.affiliation: Departamento De Análises Clínicas, Universidade Estadual De Maringá, Maringá, PR, Brazil.
authors.forename: Luiza Tamie
authors.initials: LT
authors.lastname: Tsuneto
authors.affiliation: Departamento De Genética, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.
authors.forename: Mara Helena
authors.initials: MH
authors.lastname: Hutz
mesh_terms: D000885:Anthropology, Physical; D005819:Genetic Markers / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics*; D007199:Indians, South American / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D013020:South America; D051193:Toll-Like Receptors / Q000235:genetics
chemical_list: D005819:Genetic Markers; D051193:Toll-Like Receptors
keywords: Amerindian demography; Amerindians; innate immune genes; natural selection; pathogens