Duffy blood group genotypes among African-Brazilian communities of the Amazon region

Duffy blood group genotype was studied in 95 unrelated subjects from four African-Brazilian communities of the Amazon region: Trombetas, Pitimandeua, Curiau, and Mazagao Velho. Genotyping was performed using an allele-specific primer polymerase chain reaction tech- nique for determining the three major alleles at FY blood group, and as expected, FY*O allele was the most common one, with frequencies ranging from 56.4% in Mazagao Velho to 72.2% in Pitimandeua, whereas the FY*O/FY*O genotype was found with frequencies between 32.3% in Mazagao Velho and 58.8% in Curiau. Genotype and allele distribu- tions in the four Amazonian communities are consistent with a predomi- nantly African origin with some degree of local differentiation and ad- mixture with people of Caucasian ancestry and/or Amerindians. These results reveal that the impact of the FY*O/FY*O genotype on the trans- mission and endemicity of the vivax malaria deserves to be investigated in full detail in an attempt to identify the contribution of host biological