The previously described state of the sickle-cell gene in African Americans since malaria was eliminated in the United States is an example of:
A) genetic drift.
B) disruptive selection.
C) the founder effect.
D) directional selection.

Question

Quizplus · Accepted Answer

The decrease in the frequency of the sickle-cell gene in African Americans after the elimination of malaria in the United States is an example of directional selection. This is because the selective pressure that favored the sickle-cell trait (protection against malaria) was removed, leading to a decrease in the gene's prevalence. Directional selection occurs when an environmental change favors a specific allele or genetic trait, leading to a shift in the population's genetic variance over time.

The Previously Described State of the Sickle-Cell Gene in African