Enter your genotype counts (AA, Aa, aa) or phenotype counts into the Gene Frequency Calculator to find your major allele frequency (p) and minor allele frequency (q), plus expected Hardy-Weinberg genotype frequencies and total population size.
Allele p Frequency (Major)
--
Allele q Frequency (Minor)
--
Total Individuals
--
Expected AA (p²)
--
Expected Aa (2pq)
--
Expected aa (q²)
--
Allele frequency is the proportion of a particular allele among all alleles at a specific locus in a population. It represents how common or rare an allele is and ranges from 0 (absent) to 1 (fixed in population).
For genotype counts: p = (2×AA + Aa) / (2×N) and q = (2×aa + Aa) / (2×N), where N is total individuals. From phenotype data with Hardy-Weinberg: q = √(recessive frequency) and p = 1 - q.
The Hardy-Weinberg equation is p² + 2pq + q² = 1, representing expected genotype frequencies in a population. p² is homozygous dominant frequency, 2pq is heterozygous frequency, and q² is homozygous recessive frequency.
For multiple alleles, count each allele type across all individuals and divide by total alleles. For three alleles (A, B, C): freq(A) = (2×AA + AB + AC) / (2×N). All frequencies must sum to 1.
P typically represents the frequency of the dominant or major allele, while Q represents the frequency of the recessive or minor allele. Together, p + q = 1 in a two-allele system.
Minor allele frequency (MAF) is calculated as the frequency of the less common allele. Count all copies of the minor allele and divide by total alleles (2 × total individuals). MAF is often expressed as a percentage.
Assume Hardy-Weinberg when the population has random mating, no mutations, no selection, no gene flow, and large population size. It's useful for calculating expected frequencies from phenotype data.