What this calculator does
Allele frequency from genotype counts works out direct-count allele frequencies for a two-allele gene from observed genotype numbers in a sample. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
The inputs explained
| Field | What to enter |
|---|---|
| Homozygous dominant count (AA) | A number. Starts at 50. |
| Heterozygous count (Aa) | A number. Starts at 40. |
| Homozygous recessive count (aa) | A number. Starts at 10. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with homozygous dominant count (aa)
Every other input is held at the calculator’s starting values while homozygous dominant count (aa) varies. Select any row to load that scenario into the calculator.