title: Molecular analysis of the O alleles at the blood group ABO locus in populations of different ethnic origin reveals novel crossing-over events and point mutations.
abstract: The blood group ABO genotypes of 138 group O individuals with three different ethnic origins in Brazil were determined, including Whites, Blacks and Amerindians. Several previously undescribed O alleles were found, predominantly in the Black group, in which about a third of the samples did not conform to previously known O allele structures. It has been well documented for the first time that some new alleles can arise from crossing-over events between known alleles in the ABO system. This was made possible by both restriction endonuclease analysis and direct sequencing of exons 3-7 in the ABO gene. The anticipated relatively high frequency of some of these new alleles in certain populations, necessitates great care when interpreting results from existing genotype screening methods.
authors.affiliation: Blood Centre, University Hospital, Lund, Sweden.
authors.forename: M L
authors.initials: ML
authors.lastname: Olsson
authors.forename: J F
authors.initials: JF
authors.lastname: Guerreiro
authors.forename: M A
authors.initials: MA
authors.lastname: Zago
authors.forename: M A
authors.initials: MA
authors.lastname: Chester
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000483:Alleles; D001938:Brazil; D003434:Crossing Over, Genetic; D005006:Ethnicity; D006801:Humans; D017354:Point Mutation
chemical_list: D000017:ABO Blood-Group System