Origin of Hb A2' (Hb B2) [delta16(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 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 delta-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 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.
Bennani
Mohcine
M
Laboratory of Molecular Genetics, Department of Life Sciences, Faculty of Science and Technology of Tangier, Tangier, Morocco.
Mombo
Landry-Erik
LE
Chaventre
André
A
Barakat
Amina
A
Ducrocq
Rolande
R
Nagel
Ronald L
RL
Krishnamoorthy
Rajagopal
R
D019943:Amino Acid Substitution; D001120:Arginine; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D006580:Genetic Carrier Screening; D014644:Genetic Variation; D005914:Globins / Q000235:genetics*; D005998:Glycine; D006443:Hemoglobin A2 / Q000235:genetics*; D006801:Humans; D008302:Mali; D005810:Multigene Family; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length
D003062:Codon; D005914:Globins; D006443:Hemoglobin A2; D001120:Arginine; D005998:Glycine