Beta s haplotype diversity in Afro-Americans, Africans, and Euro-Asiatics: an attempt at a synthesis

RESUMO

A review was made of the distribution of the five common betas haplotypes in eight Euro-Asian, 16 African and 12 American population (total 3,701 chromosomes). Considering the most frequent haplotype in each population discloses a clearly discontinuous pattern, the Euro-Asian groups presenting higher than 50 percent of their specific (Arab-Asian) haplotype, Africans three distinct categories (respectively higher prevalences of the Bantu, Benin and Senegal haplotypes), and the Americas showing higher frequencies of Benin in the North and Caribbean area, and Bantu in Mexico and Brazil. A dendrogram confirms these results, with the American populations being placed in an intermediary position. Genetic diversity analysis did not clearly separate the African clusters. Total diversity was similar in Africa and the Americas (0.689 and 0.622, respectively), with a higher interpopulation diversity in the former (62 percent versus 12 percent). Total genetic diversity considering Brazil only, as opposed to all America, yielded equivalent results (0.435, 0.622) but the interpopulation variability within Brazil is lower (6 percent versus 12 percent). Generally, the results showed a remarkable similarity with what would be expected taking into consideration the historical sources concerning African migrations.