BiologyGeneticsA-Level
CambridgeOCREdexcelWJECAPCBSEIEBAbitur

Gene Frequency Calculator

Calculate allele (gene) frequency in a population.

Use the free calculatorCheck the variablesOpen the advanced solver
Open Advanced Calculator
This is the free calculator preview. Advanced walkthroughs stay in the app.
Result
Ready
Allele Frequency

Formula first

Overview

Allele frequency measures the relative proportion of a specific genetic variant at a locus within a population's gene pool. It is calculated by dividing the total number of occurrences of that allele by the total number of alleles across all individuals in the diploid population.

Symbols

Variables

p = Allele Frequency, A = Copies of Allele, N = Number of Individuals

Allele Frequency
Variable
Copies of Allele
Variable
Number of Individuals
Variable

Apply it well

When To Use

When to use: This formula is applied when analyzing the genetic structure of a diploid population to observe how specific traits are distributed. It is a prerequisite for Hardy-Weinberg calculations and is used to detect changes in genetic diversity over generations.

Why it matters: Tracking allele frequencies allows biologists to monitor evolution in real-time, identifying factors like natural selection or genetic drift. This data is also vital in conservation biology to assess the genetic health and viability of endangered species.

Avoid these traps

Common Mistakes

  • Forgetting the 2N denominator.
  • Using individuals instead of alleles.

One free problem

Practice Problem

In a population of 500 flowering plants, researchers found 300 copies of the white-petal allele. Calculate the frequency of this allele in the population.

Copies of Allele300
Number of Individuals500

Solve for:

Hint: Divide the copies of the allele by twice the number of individuals.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. Campbell Biology
  2. Wikipedia: Allele frequency
  3. Griffiths, A. J. F., Wessler, S. R., Carroll, S. B., & Doebley, J. (2015). An Introduction to Genetic Analysis (11th ed.). W. H. Freeman.
  4. IUPAC Gold Book: Allele frequency
  5. Hartl, D. L., & Clark, A. G. (2007). Principles of Population Genetics (4th ed.). Sinauer Associates.
  6. AQA A-Level Biology — Populations and Evolution