Even though sickle cell confers no advantage in the malaria-free U.S.,African Americans have a relative high incidence of the gene.This is an example of

Question

Quizplus · Accepted Answer

The higher incidence of the sickle cell gene in African Americans in the U.S. can be explained by the founder effect - a situation where a smaller population breaks off from a larger one and carries only a fraction of the genetic diversity present in the original population. The higher incidence is likely due to the fact that sickle cell anemia is more prevalent in regions with high malaria rates, where the heterozygous carriers of the gene have some resistance against the disease. Therefore, the sickle cell allele would have been positively selected among African populations due to the presence of malaria, and would have been carried over to the African American population through the slave trade. However, in the malaria-free environment of the U.S., sickle cell confers no advantage and can even be a disadvantage, hence it has not been selected against in the population.

Even Though Sickle Cell Confers No Advantage in the Malaria-Free