Allele Frequency Calculator

Allele frequency is the relative proportion of a specific allele (gene variant) in a population. It's expressed as a decimal between 0 and 1, where p represents the frequency of the dominant allele and q represents the frequency of the recessive allele.

From genotype counts: p = (2×AA + Aa) / (2×N) and q = (2×aa + Aa) / (2×N), where N is total population. From phenotype data with Hardy-Weinberg assumption: q = √(recessive frequency) and p = 1 - q.

The Hardy-Weinberg equation is p² + 2pq + q² = 1, where p² represents AA frequency, 2pq represents Aa frequency, and q² represents aa frequency. This equation predicts genotype frequencies in populations that are not evolving.

P represents the frequency of the dominant allele in a population, while Q represents the frequency of the recessive allele. Since these are the only two alleles for a given gene, p + q always equals 1.

Minor allele frequency (MAF) is the frequency of the less common allele in a population. Calculate both p and q, then the MAF is whichever value is smaller. MAF is important in genetics research and disease association studies.

Hardy-Weinberg equilibrium applies when there's no mutation, migration, selection, or non-random mating, and the population is large. While real populations rarely meet all conditions perfectly, it provides a useful baseline for comparison.

Genotype frequency uses actual counts of AA, Aa, and aa individuals to directly calculate allele frequencies. Phenotype frequency uses observable traits (dominant vs recessive) and requires Hardy-Weinberg assumptions to estimate underlying genotype frequencies.