Which is not a condition for Hardy-Weinberg equilibrium?

A) Absence of gene flow

B) Absence of differential survival among genotypes

C) Random mating of individuals with respect to genotype

D) Absence of genetic drift that would cause chance fluctuations of allele frequencies

E) Small population size

The correct answer is E) Small population size

Explanation:

Hardy-Winberg Equilibrium is achieved in a population when alleles and genotypes remain constant over time; this means the population does not change or evolves. This occurs when there is not genetic flow, sexual selection, gene flow, mutation, among others.

In this context, small population size is not a condition for Hardy-Weinberg equilibrium because this does not guarantee the population will not change; indeed, small population are more prompt to genetic drift that causes alleles to change in a population as a result of random sampling; this effect has a larger impact on small populations as changes in allele frequencies in a few individuals had a great impact in small populations.