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Sickle gene. Its origin and diffusion from West Africa
The Journal of Clinical Investigation
|September 1, 1981
Summary
Genetic studies reveal distinct beta S-gene origins in West Africa. Different DNA variations (Hpa 1 fragments) show the beta S (sickle cell) and beta C genes evolved separately in regions like Togo and Ivory Coast.
Area of Science:
- Population genetics
- Molecular evolution
- Human genetics
Background:
- Beta S (sickle cell) and beta C gene mutations are prevalent in West Africa.
- DNA polymorphisms aid in understanding structural gene mutation evolution.
Purpose of the Study:
- To analyze the linkage of beta S and beta C genes to a polymorphic Hpa 1 site in West African populations.
- To investigate the evolutionary origins and spread of beta S-genes in the region.
Main Methods:
- Analysis of DNA polymorphisms, specifically the Hpa 1 site located 3' to the beta-globin gene locus.
- Genotyping of beta A, beta S, and beta C genes in selected West African populations.
Main Results:
- A significant frequency (17-18%) of beta A-genes linked to 13-kilobase Hpa 1 fragments was identified.
- Beta S and beta C genes in Togo are strongly associated with the 13-kilobase Hpa 1 fragment.
- In Ivory Coast, 72% of beta S-genes are linked to the 7.6-kilobase Hpa 1 fragment.
Conclusions:
- Evidence suggests the selection and expansion of at least two distinct beta S-gene chromosomes in West Africa.
- These findings support independent evolutionary events for beta S-genes in geographically proximate yet ethnically diverse areas.
- The study indicates subsequent diffusion of these beta S-gene variants across Africa.
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