In the Hardy-Weinberg equilibrium equation, what does Q represent?

In the Hardy-Weinberg equilibrium equation, Q represents the frequency of the homozygous recessive genotype. The equation itself is typically expressed as p² + 2pq + q² = 1, where p represents the frequency of the dominant allele, q represents the frequency of the recessive allele, and q² denotes the frequency of the homozygous recessive genotype. This concept is fundamental in population genetics, as it allows scientists to predict genetic variations in a population that is not evolving.

Understanding this equation is crucial because it assumes five conditions: a very large population, no mutation, no migration, random mating, and no selection. When these conditions are met, the allele frequencies will remain constant from generation to generation, providing a baseline for comparing actual population data. In practical terms, if you measure the frequency of the homozygous recessive individuals in a population, you can deduce the value of q² and then calculate other genotypic frequencies accordingly.