What is the equation that represents the sum of allele frequencies in a population?

The equation that represents the sum of allele frequencies in a population is P + Q = 1. In this context, P and Q are used to denote the frequencies of two alleles at a given locus, typically referring to one dominant and one recessive allele within a gene. This equation stems from the Hardy-Weinberg principle, which suggests that allele frequencies in a large, randomly-mating population tend to remain stable over generations in the absence of evolutionary influences. When P represents the frequency of the dominant allele and Q represents the frequency of the recessive allele, their total must equal 1, indicating that all alleles present in that population are accounted for.

Understanding this equation is crucial for topics around population genetics, as it helps in predicting genotypic frequencies and understanding the genetic structure of a population. The other equations listed do not correctly represent the relationship between allele frequencies in a population, either suggesting impossible scenarios or failing to account for the requirement that the frequencies must sum to 1.