title: ABO blood group in Amerindians from Brazilian Amazon.
abstract: BACKGROUND
  The Parakanã is a group of Indians with cultural similarities to the extinct Tupi group. They are an isolated native population from East Brazilian Amazon. A number of different O alleles have been found at the blood group ABO locus in populations of several ethnic origins (Caucasians, Blacks, Amerindians).
  
  
  OBJECTIVE
  The present study describes the ABO blood group polymorphism gene of the Parakanã Indians. The Amerindian group was carefully selected for racial background.
  
  
  METHODS
  The blood group polymorphism was analysed in genomic DNA from 62 Parakanã Indians. We determined the 261G deletion, the T646A and C771T mutations described in O(1variant) and the G542A substitution, using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism).
  
  
  RESULTS
  All Amerindians studied were homozygous for the 261G deletion. The frequencies of the T646A and C771T mutations in Parakanãs (0.65) were lower than that observed in Kayapo, Yanomama and Arara Indians (0.91) (chi (2) = 18.24; p-v < 0.001. The G542A substitution in Parakanãs was also lower (0.22) than in other tribes (0.42) (chi(2) = 9.73; p-v = 0.001).
  
  
  CONCLUSIONS
  The different O alleles including the G542A mutation are not distributed homogeneously among all Amazonian Amerindians. Our results are in agreement with other genetic markers studied previously in Parakanã Indians, whose distinct genetic pattern differs from Europeans and even from other Amerindians.
authors.affiliation: Centro de Hematologia e Medicina Transfusional, Universidade Estadual de Campinas, UNICAMP, São Paulo, Brazil. maluz@unicamp.br
authors.forename: M L
authors.initials: ML
authors.lastname: Barjas-Castro
authors.forename: M C P
authors.initials: MC
authors.lastname: Soares
authors.forename: R C
authors.initials: RC
authors.lastname: Menezes
authors.forename: M H M
authors.initials: MH
authors.lastname: Carvalho
authors.forename: F F
authors.initials: FF
authors.lastname: Costa
authors.forename: S T O
authors.initials: ST
authors.lastname: Saad
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001938:Brazil; D002648:Child; D004247:DNA / Q000097:blood / Q000235:genetics; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D005787:Gene Frequency; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic
chemical_list: D000017:ABO Blood-Group System; D004247:DNA