recessive allele, can be used to determine the genotypic ratios caused by the alleles. Thus, equals the frequency of the homozygous dominant genotype, 2pq equals the total of the all the frequencies of the heterozygous genotypes, and equals the frequency of the homozygous recessive genotype. For each additional allele considered, another term must be added to the equation. For example, the consideration of the frequencies of three alleles requires the trinomial equation .
