How can the genotype frequency of heterozygous individuals (Rr) be calculated in a population?

The genotype frequency of heterozygous individuals (Rr) in a population can be calculated using the formula 2pq, where p represents the frequency of the dominant allele (R) and q represents the frequency of the recessive allele (r). This equation is derived from the Hardy-Weinberg principle, which applies to populations that are not evolving. According to this principle, the allele frequencies remain constant from generation to generation if certain conditions are met, such as large population size and random mating.

In this context, the term "heterozygous" refers to individuals that have one copy of the dominant allele and one copy of the recessive allele. The term 2pq specifically accounts for the presence of these heterozygous individuals by considering the ways this combination can occur among the alleles in the population. Therefore, 2pq is essential for estimating the frequency of heterozygotes when given allele frequencies.

Other formulas provided in the choices refer to different genotype frequencies. For instance, p^2 calculates the frequency of homozygous dominant individuals (RR), while q^2 calculates the frequency of homozygous recessive individuals (rr). The equation p + q simply represents the sum of the allele frequencies in a population