Origin of Hb A2′ (Hb B2) [δ16(A13)Gly→Arg (GGC→CGC)]

On a field trip to the Dogon country (le Pays Dogon) in central Mali, we detected a high frequency of the Hb A(2) abnormality, reaching higher numbers among blacksmiths (up to 12.4%) living in the same villages. In this report, by direct nucleotide sequencing and employing a polymerase chain reaction-restriction fragment length polymorphism approach, we show that the Hb A(2) variant observed in the Dogon population is indeed Hb A'(2), also called Hb B-2, and that in all of the cases the abnormal delta-globin gene is linked to a unique haplotype. The same haplotype was found linked to Hb A'(2) in the Herero population belonging to the South African Bantu-speaking Blacks from Namibia. Although the unique origin of this mutation in Africa is a possibility; a recurrent mutational event cannot be excluded because the linked beta cluster haplotype is one of the two major haplotypes found in all African populations. A study of populations from other regions of Africa is required to clarify this issue,