National League for Nursing (NLN PAX) Practice Exam

Which condition must be met for a population to be in Hardy-Weinberg equilibrium?

1. The population has a genetic mutation.

2. The population is isolated from other populations.

3. The population experiences natural selection.

4. The population has high mutation rates.

The correct answer is: The population is isolated from other populations.

For a population to be in Hardy-Weinberg equilibrium, it is necessary that there is no gene flow from other populations, meaning that the population must be isolated. When a population is isolated, it prevents the introduction of new alleles and maintains the existing allele frequencies over generations, ensuring that all five conditions of Hardy-Weinberg equilibrium are met: no mutations, no gene flow, a large population size, random mating, and no natural selection. The isolation allows for a stable genetic environment where allele frequencies can be calculated and predicted based on the original genetic makeup of the population. This equilibrium provides a baseline for studying evolutionary processes, as any deviations from Hardy-Weinberg equilibrium in the population can indicate that one or more of the conditions has been violated, leading to changes in allele frequencies over time.