A balanced polymorphism that is maintained because the advantageous phenotypes only retain their advantage when they are present below a certain frequency is called __________.
A) heterosis
B) hybrid vigor
C) a frequency-dependent balanced polymorphism
D) a heterozygous advantage

Question

Quizplus · Accepted Answer

In a frequency-dependent balanced polymorphism, the advantage of a particular phenotype depends on its frequency in the population. When the frequency of the advantageous phenotype is low, it has a selective advantage, but as its frequency increases, the advantage decreases, leading to the maintenance of multiple alleles at high frequencies in the population. Heterosis refers to the increased fitness of hybrid offspring compared to their parents, hybrid vigor is another term for heterosis, and a heterozygous advantage refers to the greater fitness of heterozygous individuals compared to homozygous individuals for a particular trait. None of these terms fully describe the maintenance of an advantageous phenotype at low frequencies due to frequency-dependent selection.

A Balanced Polymorphism That Is Maintained Because the Advantageous Phenotypes