Answer :
Final answer:
A population's genotypic frequencies remain constant in Hardy-Weinberg equilibrium, a theoretical state where evolution does not occur, if there are no mutations, no migration, large population size, random mating, and no natural selection. True equilibrium is rare as natural populations are usually subject to evolutionary forces.
Explanation:
Hardy-Weinberg Equilibrium and Stable Genotypic Frequencies
If a population meets certain conditions, then genotypic frequencies remain constant from one generation to the next. This is known as the Hardy-Weinberg equilibrium. The key conditions that need to be met for a population to be in Hardy-Weinberg equilibrium are:
- No new mutations occurring, maintaining the same alleles in the gene pool.
- No migration, ensuring that the allele frequencies are not altered by individuals moving into or out of the population.
- A very large population size to minimize the effects of genetic drift.
- Random mating among individuals, meaning that there is no mate selection based on genotype which could affect allele frequencies.
- No natural selection, so all individuals have an equal chance to reproduce and pass on their genes.
If these conditions are met, in theory, the allele and genotype frequencies would stay the same over generations, indicating no evolution within the population. However, in nature, populations are subject to evolutionary forces such as drift, mutation, migration, and selection, making true Hardy-Weinberg equilibrium unlikely. Scientists use the Hardy-Weinberg principle as a mathematical model to compare with actual populations to infer which evolutionary forces could be influencing genetic change.
