title: Sickle gene. Its origin and diffusion from West Africa.
abstract: Linked DNA polymorphisms can be used to study the evolution of structural gene mutations. Both the beta S-(beta 6Glu leads to Val) and beta C-(beta 6Glu leads to Lys) genes are common in West Africa. We have analyzed their linkage to a polymorphic Hpa 1 site appearing 3' to the beta-globin gene locus in selected populations from Wes Africa. A large reservoir of beta A-genes linked to 13-kilobase Hpa 1 fragments with a frequency of 17-18% has been identified. In addition, the beta S- and beta C-genes in Togo are found to be tightly linked to the 13-kilobase Hpa 1 fragment, whereas 72% of the beta S-genes in the Ivory Coast reside on the 7.6-kilobase Hpa 1 fragment. These studies are consistent with the selection and expansion of two different chromosomes bearing beta S-genes in at least two physically close, but ethnically separate regions of West Africa, with subsequent diffusion to North, Equatorial, and East Africa.
mesh_terms: D000349:Africa / Q000208:ethnology; D000755:Anemia, Sickle Cell / Q000235:genetics*; D005075:Biological Evolution; D004262:DNA Restriction Enzymes; D005796:Genes; D005828:Genetics, Population; D006451:Hemoglobin, Sickle / Q000235:genetics*; D006801:Humans; D011110:Polymorphism, Genetic
chemical_list: D006451:Hemoglobin, Sickle; D004262:DNA Restriction Enzymes