Allele Frequency Calculator

Calculate allele and genotype frequencies, Hardy-Weinberg equilibrium, and more.

Enter the number of individuals for each genotype or directly input allele counts. This tool computes allele frequencies (p, q), Hardy-Weinberg equilibrium, and genotype frequencies. Useful for population genetics, biology classes, and research.

Examples

See how to use the calculator with real-world scenarios.

Classic Hardy-Weinberg Example

Genotype Counts

A population with 50 AA, 30 Aa, and 20 aa individuals.

AA individuals: 50 individuals

Aa individuals: 30 individuals

aa individuals: 20 individuals

Mostly Heterozygotes

Genotype Counts

A population with 10 AA, 80 Aa, and 10 aa individuals.

AA individuals: 10 individuals

Aa individuals: 80 individuals

aa individuals: 10 individuals

Direct Allele Counts

Allele Counts

A sample with 120 A alleles and 80 a alleles.

A alleles: 120 alleles

a alleles: 80 alleles

Total individuals: 100 individuals

Small Population

Genotype Counts

A small group: 3 AA, 2 Aa, 5 aa individuals.

AA individuals: 3 individuals

Aa individuals: 2 individuals

aa individuals: 5 individuals

Other Titles
Understanding Allele Frequency: A Comprehensive Guide
Master the concepts of allele frequency and Hardy-Weinberg equilibrium with this in-depth resource.

What is Allele Frequency?

  • Definition of allele frequency
  • Why allele frequency matters
  • Allele frequency in population genetics
Allele frequency refers to how common a particular allele is in a population. It is a fundamental concept in population genetics, helping scientists understand genetic diversity and evolutionary processes.
Allele Frequency Formula
The frequency of an allele (e.g., A or a) is calculated as the number of copies of that allele divided by the total number of alleles for that gene in the population.

Allele Frequency Examples

  • If a population has 100 individuals (200 alleles) and 120 are A, the frequency of A is 120/200 = 0.6.
  • If there are 50 AA, 30 Aa, and 20 aa, then p = (2*50 + 30)/(2*100) = 0.65.

Step-by-Step Guide to Using the Calculator

  • Input genotype or allele counts
  • Review calculated frequencies
  • Interpret Hardy-Weinberg results
Start by entering the number of individuals for each genotype (AA, Aa, aa) or directly input the number of A and a alleles if known. The calculator will compute allele frequencies and Hardy-Weinberg equilibrium values.
How to Use the Calculator
After entering your data, click 'Calculate' to see the results. Use the 'Reset' button to clear all fields and start over.

Step-by-Step Examples

  • Input: AA=40, Aa=40, aa=20. Output: p=0.6, q=0.4.
  • Input: A alleles=120, a alleles=80. Output: p=0.6, q=0.4.

Real-World Applications of Allele Frequency

  • Tracking genetic diseases
  • Studying evolution
  • Conservation biology
Allele frequency calculations are used in medical genetics to track disease alleles, in evolutionary biology to study natural selection, and in conservation to monitor genetic diversity.
Applications in Research and Education
Students, teachers, and researchers use allele frequency data to understand population structure and evolutionary trends.

Application Examples

  • Tracking the frequency of a disease allele in a population over time.
  • Comparing allele frequencies between different populations to study migration.

Common Misconceptions and Correct Methods

  • Allele vs. genotype frequency
  • Hardy-Weinberg assumptions
  • Interpreting results correctly
A common mistake is confusing allele frequency with genotype frequency. The calculator helps clarify these concepts and ensures accurate calculations.
Avoiding Calculation Errors
Always double-check that the sum of allele counts matches twice the number of individuals, and that frequencies are between 0 and 1.

Misconception Examples

  • Entering genotype counts instead of allele counts by mistake.
  • Forgetting to double the number of individuals when calculating total alleles.

Mathematical Derivation and Examples

  • Deriving allele frequency formulas
  • Hardy-Weinberg equilibrium math
  • Worked calculation examples
The frequency of allele A (p) is calculated as: p = (2AA + Aa) / (2N). The frequency of allele a (q) is: q = (2aa + Aa) / (2N). Under Hardy-Weinberg equilibrium, expected genotype frequencies are p² (AA), 2pq (Aa), and q² (aa).
Worked Example
If AA=50, Aa=30, aa=20: N=100, total alleles=200. p=(250+30)/200=0.65, q=(220+30)/200=0.35. Expected AA=0.65²100=42.25, Aa=20.650.35100=45.5, aa=0.35²*100=12.25.

Mathematical Examples

  • AA=50, Aa=30, aa=20: p=0.65, q=0.35, expected AA=42.25, Aa=45.5, aa=12.25.
  • A alleles=120, a alleles=80: p=0.6, q=0.4, expected AA=36, Aa=48, aa=16 (for N=100).