Question

An African American couple has produced two children with sickle cell disease. They have asked why this disease seems to be more common in the African American population than in other U.S. populations. Which of the following factors provides the best explanation?

A. Consanguinity
B. Genetic drift
C. Increased gene flow in this population
D. Increased mutation rate in this population
E. Natural selection

Answer 1

The increased prevalence of sickle cell disease in the African American population compared to other populations in the United States can be explained by natural selection.

Step-by-step explanation:

The best explanation for the increased prevalence of sickle cell disease in the African American population compared to other populations in the United States is natural selection.

Researchers have found that individuals who are heterozygous for the sickle cell mutation, meaning they have one normal hemoglobin gene and one sickle cell gene, are protected against malaria. This protective effect against malaria has led to a higher frequency of the sickle cell gene in regions where malaria is endemic, such as Africa.

While the sickle cell gene can cause sickle cell disease in individuals who are homozygous for the mutation, it continues to be more common in the African American population due to the survival advantage heterozygotes have against malaria.