What is overdominance hypothesis?
Overdominance hypothesis: The overdominance hypothesis states that an organism that descends from parents of different genetic backgrounds will have greater resistance to a broader spectrum of potential dangers.
What is overdominance in biology?
Overdominance. In some instances, offspring can demonstrate a phenotype that is outside the range defined by both parents. In particular, the phenomenon known as overdominance occurs when a heterozygote has a more extreme phenotype than that of either of its parents.
What is overdominance hypothesis of heterosis?
The overdominance hypothesis attributes heterosis to the superior fitness of heterozygous genotypes over homozygous genotypes at a single locus (East 1908; Shull 1908).
Does overdominance reduce genetic variation?
This situation, known as heterosis or overdominance, leads to the stable coexistence of both alleles in the population and hence contributes to the widespread genetic variation found in populations of most organisms.
How does overdominance affect evolution?
Does overdominance maintain genetic variation?
One of the classic ways to maintain genetic variation with a population is “overdominance,” in short, a state where heterozygotes exhibit greater fitness than the homozygote genotypes.
What is overdominance gene action?
Overdominance is a condition in genetics where the phenotype of the heterozygote lies outside the phenotypical range of both homozygous parents. Overdominance can also be described as heterozygote advantage, wherein heterozygous individuals have a higher fitness than homozygous individuals.
How do you determine overdominance?
Overdominance. Overdominance occurs when fitness of the heterozygote is superior to that of either homozygote. The result is that both alleles are maintained in the population at an equilibrium frequency ( , read “q hat”, where q = 0) that maximizes fitness.
How does overdominance affect evolutionary process?
How does overdominance maintain genetic variation?
Overdominance maintains both alleles in the population to achieve the maximum overall fitness for a population (Figure 23). The equilibrium frequencies depend on the values of the selection coefficients, s and t, regardless of the initial allele frequencies. The equilibrium at this point is stable.