Under Hardy-Weinberg equilibrium, allele frequencies stay constant if there is no mutation, the population is large, mating is random, there is no migration, and no natural selection. Which option reflects these conditions?

Under Hardy-Weinberg equilibrium, allele frequencies stay constant if there is no mutation, the population is large, mating is random, there is no migration, and no natural selection. Which option reflects these conditions?

• A. Large populations, random mating, no migration, no mutations, and no natural selection
• B. No mutations
• C. Natural selection
• D. Small populations

Answer: (A)

Under Hardy-Weinberg equilibrium, allele frequencies stay constant from one generation to the next only when no evolutionary forces act on the population. That means there is no mutation introducing new alleles, no migration exchanging alleles with other populations, mating occurs randomly, the population is large enough to avoid genetic drift, and there is no natural selection favoring any genotype. The option that lists large populations, random mating, no migration, no mutations, and no natural selection matches all of these conditions, so it best reflects the scenario where allele frequencies remain constant. If any of these conditions are violated—such as a small population causing genetic drift, natural selection changing fitness, or migration or mutation introducing new alleles—allele frequencies would shift over time.

Under Hardy-Weinberg equilibrium, allele frequencies stay constant from one generation to the next only when no evolutionary forces act on the population. That means there is no mutation introducing new alleles, no migration exchanging alleles with other populations, mating occurs randomly, the population is large enough to avoid genetic drift, and there is no natural selection favoring any genotype. The option that lists large populations, random mating, no migration, no mutations, and no natural selection matches all of these conditions, so it best reflects the scenario where allele frequencies remain constant. If any of these conditions are violated—such as a small population causing genetic drift, natural selection changing fitness, or migration or mutation introducing new alleles—allele frequencies would shift over time.