Breeding and Genetics Exam 1 Practice

Hardy-Weinberg equilibrium holds only if there is no gene flow, meaning no migration between populations, along with no mutation, random mating, a very large population, and no differential survival (equal fitness). The idea is that allele and genotype frequencies stay the same generation after generation only when those conditions hold. Saying migration is present breaks the no-migration requirement because immigration or emigration introduces or removes alleles, shifting allele frequencies. So this option is not a condition that maintains Hardy-Weinberg equilibrium, whereas random mating, a large population, and equal fitness are the conditions that do.