Genetics & evolution · SL/HL

Allele frequency

Find allele frequencies from diploid genotype counts.

Your values

Number formats & units

Use decimal dots in datasets. Single values also accept decimal commas and scientific notation such as 1.2e-3 or 1.2 × 10⁻³.

Allele Frequency from Genotype Counts Calculator inputs

Calculated locally. No account or input upload.

Result & working

Example

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Formula & example

The relationship

p=2AA+Aa2Np=\frac{2\mathrm{AA}+\mathrm{Aa}}{2N}
q=2aa+Aa2Nq=\frac{2\mathrm{aa}+\mathrm{Aa}}{2N}
p+q=1p+q=1
What the variables mean
SymbolMeaning
NNTotal number of individuals.

Worked example

AA count
36
Aa count
48
aa count
16

p = 0.6, q = 0.4

Follow the example steps
  1. N = 36+48+16 = 100
  2. p = (2AA + Aa)/(2N) = (2×36+48)/200 = 0.6
  3. q = (2aa + Aa)/(2N) = (2×16+48)/200 = 0.4
  4. p + q = 1

Common mistakes

There are two alleles per diploid individual.

Incorrect approach

AA = 30, Aa = 40, aa = 30: p = (30 + 40)/100 = 0.7

Correct approach

p = (2 × 30 + 40)/(2 × 100) = 0.5

More checks before you submit
  • Count two alleles per diploid individual.
Method notes

This calculates observed allele frequencies; it does not by itself show whether the population is in Hardy–Weinberg equilibrium.