The HbS allele that causes sickle-cell anemia in the recessive condition is most common in areas that experience a high frequency of
A) polio.
B) typhus.
C) diphtheria.
D) malaria.
E) cystic fibrosis.

Question

Quizplus · Accepted Answer

The HbS allele provides some protection against malaria when in the heterozygous condition. Therefore, in areas where malaria is prevalent, the frequency of the HbS allele is higher due to natural selection.

The HbS Allele That Causes Sickle-Cell Anemia in the Recessive