Origin of the hemoglobin S gene in a northern Brazilian population: the combined effects of slave trade and internal migrations

We analyzed DNA polymorphisms in the beta-globin gene cluster of 30 sickle cell anemia patients from Belem, the capital city of the State of Para, in order to investigate the origin of the beta S mutation. Sixty-seven percent of the beta S chromosomes were Bantu type, 30% were Benin type, and 3% wer e Senegal type. The origin of the beta S mutation in this population, estim ated on the basis of beta S-linked haplotypes, contradicts the historical r ecords of direct slave trade from Africa to the northern region of Brazil. Historical records indicate a lower percentage of people from Benin. These discrepancies are probably due to domestic slave trade and later internal m igrations, mainly from northeastern to northern regions. Haplotype distribu tion in Belem did not differ significantly from that observed in other Braz ilian regions, although historical records indicate that most slaves from A tlantic West Africa, where the Senegal haplotype is prevalent, were destine d for the northern region, whereas the northeast (Bahia, Pernambuco and Mar anhao) was heavily supplied with slaves from Central West Africa, where the Benin haplotype predominates.