Despite causing a life-threatening disease, the sickle-cell allele in some areas of Africa has remained in high frequency in those populations because it protects against malaria. In the United States, malaria was eradicated shortly before World War II by eliminating the mosquito that spreads the disease. What is likely to happen to the frequency of the sickle-cell allele in African Americans living in the United States?

Question

Quizplus · Accepted Answer

The frequency of the sickle-cell allele is likely to decrease in African Americans living in the United States because the selective pressure for the sickle-cell allele (protection against malaria) is no longer present since malaria has been eradicated. Without this selective pressure, individuals with the sickle-cell allele are no more likely to survive and reproduce than individuals with the normal allele, so the frequency of the sickle-cell allele will decrease over time due to genetic drift and other factors.

Despite Causing a Life-Threatening Disease, the Sickle-Cell Allele in Some