Unformatted text preview: "balanced polymorphism" In turns out that the "balance" is due to fact that heterozygotes have lower rates of 1) malarial infection, and 2) malarial mortality if infected, compared to "normals" (H n H n ) In fact, studies have revealed that, because heterozygotes have higher reproductive success than normals in malaria-infested areas, the distribution of H s gene closely matches region of endemic malaria = broad band across Sub-Saharan Africa (as well as areas in E. Mediterranean, parts of So. Asia, etc.) In W. Africa, malaria is transmitted by Anopheles mosquitoes, which breed best in cleared areas (i.e., in sunlit pools, which are common in rainy season) Swidden agriculture increases cleared areas, and thus the breeding habitat of Anopheles, thereby indirectly increasing the incidence of malaria...
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- Fall '10
- Anthropology, sickle cell trait, blood disease, malarial infection