Beta-globin gene cluster haplotypes in the Mapuche Indians of Argentina

Haplotypes derived from five polymorphic restriction sites in the beta-glob in gene cluster were investigated in 86 chromosomes from the Argentinian Ma puche. These results were integrated with those previously obtained for ten Brazilian Indian tribes. Eight haplotypes were identified, the most freque nt being 2 (57%) and 6 (27%). The presence of haplotype 3 in 2% of the Mapu che chromosomes is probably an evidence of admixture with individuals of Af rican ancestry. Due to the high number of haplotypes observed, heterozygosi ty as measured by the Gini-Simpson index was higher in the Mapuche than in Brazilian Indians. The haplotypic distribution in the Mapuche was also sign ificantly different from those of all Brazilian tribes investigated. This h eterogeneity could be at least partially explained by admixture with non-In dian populations.