Final answer:
Overdominance leads to an equilibrium where heterozygote genotypes are favored and both alleles are maintained in a population, thereby preserving genetic diversity.
Step-by-step explanation:
Overdominance, also known as heterozygote advantage, refers to the phenomenon where the heterozygote genotype has a higher relative fitness than either the homozygous dominant or homozygous recessive genotype. This situation often produces a balanced polymorphism in the population, where multiple alleles are maintained at stable frequencies. In the case of overdominance, natural selection favors the heterozygote, which leads to an equilibrium where both alleles remain present in the population without one becoming fixed or lost.
This equilibrium differs from the Hardy-Weinberg equilibrium, which is a theoretical state where allele frequencies do not change due to the absence of evolutionary forces. Overdominance can, therefore, help maintain genetic diversity within a population.