Question

How can population size affect additive genetic variance in a population?

Answer 1

Additive genetic variance involves the inheritance of a particular allele from your parent and this allele's independent effect on the specific phenotype, which will cause the phenotype deviation from the mean phenotype. According to Neutral theory of quantitative genetic, reduce in population are expected to decrease standing levels of additive genetic variance of quantitative traits.However, some empirical and theoretical results suggest that, if nonadditive genetic effects influence the trait, bottlenecks may actually increase additive genetic variance.Natural populations may periodically experience fluctuations in population size. Understanding the effects of dramatic decreases in population size has been an important issue in the conservation of endangered species and in the domestication and intense selective breeding of many agricultural species. Assuming neutral and additive gene action, reduce in population are expected to decrease additive genetic variance and reduce the evolutionary potential of populations.If the genetic architecture underlying a trait is controlled by genes that are acting additively, a population reduction is predicted to reduce genetic variance proportional to the inbreeding coefficient. Thus, for additive traits, reduce in population are expected to decrease the adaptability of populations.