Question

In a population of the Yoruba ethnic group living in a region of Nigeria with a high prevalence of malarial infection, the frequency of the HbS allele for sickle-cell hemoglobin was 0.2. Suppose that individuals in this population mate randomly, and that the fitness of HbSHbS homozygotes in this environment is only 15% as high as HbAHbS heterozygotes. 1. If the frequency of the HbS allele in this population represents an equilibrium involving malaria-induced selection against HbAHbA homozygotes vs. selection against HbSHbS homozygotes, then what is the estimated relative fitness of HbAHbA homozygotes in this environment?

Answer 1

The sickle-cell allele makes it so malaria cannot reproduce, giving the person a better chance of living. This is sickle cell anemia that turns out that, in these areas, HbS carriers have been naturally selected, because the trait confers some resistance to malaria. Their red blood cells, containing some abnormal hemoglobin, tend to sickle when they are infected by the malaria parasite. ickle cell disease is the most common inherited blood disorder in the United States, affecting 70,000 to 80,000 Americans. The disease is estimated to occur in 1 in 500 African Americans and 1 in 1,000 to 1,400 Hispanic Americans.