In some parts of Africa, the frequency of heterozygosity for the sickle-cell anaemia 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) The malarial parasite changing the allele.

Question

Quizplus · Accepted Answer

The relationship between sickle-cell anaemia and a high frequency of heterozygosity in certain parts of Africa is related to Darwin's explanation of natural selection. The prevalence of the sickle-cell anaemia allele is thought to have increased in these areas because individuals who carry one copy of the allele (i.e. are heterozygous) have a selective advantage in regions where malaria is common. This is an example of natural selection favoring a particular genotype in response to environmental pressures.

In Some Parts of Africa, the Frequency of Heterozygosity for the Sickle-Cell