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Compute allele frequencies from genotype counts: p = (2AA + Aa) / 2N, q = (2aa + Aa) / 2N. Derived from Hartl & Clark 2007, Griffiths, StatPearls. Educational use only.
Execution
Fill in the form, run the tool, and review the result in one place.
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Tool usage guide
The Allele Frequency Calculator computes p and q for a biallelic locus from observed AA, Aa, and aa genotype counts. It reports the population size, total allele count, copies of each allele, and results rounded to your selected number of decimal places. Educational use only.
Background
A student is reviewing a population of 100 individuals with 36 AA, 48 Aa, and 16 aa genotypes.
Problem
Calculate the frequencies and copy counts of alleles A and a.
How to use
Enter 36 for AA count, 48 for Aa count, 16 for aa count, and select 4 decimal places.
{"AACount":36,"AaCount":48,"aaCount":16,"decimalPlaces":4}Outcome
The result is N = 100 and totalAlleles = 200, with p = 0.6, q = 0.4, countA = 120, and counta = 80.
Background
An exercise uses 200 individuals: 160 are AA, 36 are Aa, and 4 are aa.
Problem
Determine the frequency of the recessive allele from the observed genotype counts.
How to use
Enter 160 for AA count, 36 for Aa count, 4 for aa count, and keep the decimal setting at 4.
{"AACount":160,"AaCount":36,"aaCount":4,"decimalPlaces":4}Enter the observed counts for AA, Aa, and aa genotypes.
p = (2AA + Aa) / 2N, where N is the total number of individuals.
q = (2aa + Aa) / 2N.
Each diploid individual carries two alleles at the locus, so N individuals provide 2N alleles.
Yes. Decimal Places can be set from 0 to 8, with 4 as the default.
Outcome
The result is N = 200 and totalAlleles = 400, with p = 0.89, q = 0.11, countA = 356, and counta = 44.