The frequency of heterozygosity for the sickle-cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following?
A) Mendel's law of independent assortment
B) Mendel's law of segregation
C) Darwin's explanation of natural selection
D) Darwin's observations of competition
E) the malarial parasite changing the allele

Question

Quizplus · Accepted Answer

The relationship described is an example of natural selection, as individuals who are heterozygous for the sickle-cell anemia allele have an advantage in regions with high malaria prevalence. This allows them to survive and reproduce at a higher rate than individuals with only one normal allele or two sickle-cell alleles, increasing the frequency of the sickle-cell allele in the population despite its harmful effects in homozygotes. This is an example of Darwin's theory of natural selection.

The Frequency of Heterozygosity for the Sickle-Cell Anemia Allele Is