Positive selection increases the frequency of an allele (until it goes to fixation) and negative selection decreases the frequency of an allele (until it is eliminated). What is the long-term fate of either allele of a gene with two alleles in which the fitness of the heterozygote is superior to that of both homozygotes?
A)One allele will eventually go to fixation because it is still more favored than the other with the given selective environment.
B)Both alleles will remain in the population because heterozygote gametes will form with each allele in a separate gamete.
C)Heterozygote advantage will continue until the frequency of both alleles is equal to 0.5.
D)One of the alleles will eventually be lost because selection will favor the other allele.

Question

Quizplus · Accepted Answer

In the scenario described, both alleles will remain in the population because the heterozygote has a fitness advantage over both homozygotes. This will result in a stable equilibrium in which both alleles persist. This phenomenon is called balanced polymorphism.

Positive Selection Increases the Frequency of an Allele (Until It