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

Abstract

On a field trip to the Dogon country (le Pays Dogon) in central Mali, we detected a high frequency of the Hb A₂ 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 A₂ variant observed in the Dogon population is indeed Hb A₂^′, also called Hb B₂, and that in all of the cases the abnormal δ‐globin gene is linked to a unique haplotype. The same haplotype was found linked to Hb A₂^′ 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 β 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.

• Dogon country (le Pays Dogon)
• DNA polymorphism
• β gene
• Hb B₂