If a disease eliminates all heterozygous individuals in a Hardy-Weinberg population, how long will it take to return to equilibrium?

The concept of Hardy-Weinberg equilibrium is based on several assumptions, including large population size, no mutation, no migration, random mating, and no selection. When a disease eliminates all heterozygous individuals from a population, it disrupts this equilibrium by removing genetic variation.

If only heterozygous individuals are eliminated, the genetic structure of the population changes, and it can significantly shift allele frequencies. After this disturbance, the population can achieve a new equilibrium relatively quickly. In this case, the most straightforward answer is that it can return to equilibrium in one generation since the next generation will reflect the changes in allele frequencies caused by the elimination of heterozygotes.

After one generation, the homozygous individuals that remain will both reproduce, leading to the establishment of a new population structure that can be assessed using the Hardy-Weinberg principle again. Each generation thereafter continues to reinforce this new allele frequency unless further disruptive factors are introduced to the population.

While longer time frames like ~400 or ~4,000 generations may be considered under different scenarios involving more complex dynamics or additional factors, in this situation, the immediate response is seen within just one generation.