Question

In a population, stabilizing selection is the result of

• A. Founder effect
• B. Heterozygote advantage
• C. Population bottleneck
• D. Random mating
• E. Reproductive isolation

Answer 1

Answer: (B)

Heterozygote advantage

Stabilizing selection in a population acts against extremes and favors intermediate phenotypes. This refers often to heterozygous advantage, in which natural selection favors the heterozygote because it possesses benefits that homozygotes lack. In other words, a heterozygous advantage describes the heterozygote genotype which has a higher relative fitness than the homozygote dominant or homozygote recessive genotype. For example, people with homozygous recessive for sickle cell anemia, meaning they have the disease, are also immune to malaria, a disease common in Africa, where sickle cell originated. Those heterozygous for the trait show no symptoms of sickle cell, but they are immune to malaria, greatly benefitting the heterozygote.

Thus, the correct answer is option 'Heterozygote advantage'.