Example Data Table
| Sample |
AA |
Aa |
aa |
p |
q |
Expected Aa |
| Class sample |
36 |
48 |
16 |
0.6000 |
0.4000 |
48.0000 |
| Field group |
50 |
40 |
10 |
0.7000 |
0.3000 |
42.0000 |
| Lab group |
25 |
50 |
25 |
0.5000 |
0.5000 |
50.0000 |
Formula Used
Total individuals: N = AA + Aa + aa
Total alleles: 2N
A allele count: 2AA + Aa
a allele count: 2aa + Aa
A allele frequency: p = A allele count / 2N
a allele frequency: q = a allele count / 2N
Expected genotype frequencies: AA = p², Aa = 2pq, aa = q²
Expected genotype counts: expected frequency × N
Observed heterozygosity: Ho = Aa / N
Expected heterozygosity: He = 2pq
Inbreeding coefficient: F = 1 - Ho / He
Chi-square: Σ((observed - expected)² / expected)
How to Use This Calculator
Enter the count for each genotype group. Use AA for homozygous dominant individuals. Use Aa for heterozygous carriers. Use aa for homozygous recessive individuals.
Add a sample name and population label for better records. Enter a projected population size when you want carrier or recessive case estimates. Choose a significance level for the Hardy-Weinberg balance note.
Press Calculate to show results below the header and above the form. Use the CSV option for spreadsheets. Use the PDF option for a simple report file.
Allele Frequency Calculator Guide
An allele frequency calculator helps estimate how common each allele is in a sample. It uses genotype counts and converts them into allele counts. This is useful in population studies, classroom genetics, breeding records, and laboratory reports. The tool accepts AA, Aa, and aa counts. It then finds the total number of individuals and alleles.
Why Allele Frequency Matters
Allele frequency shows the share of a gene variant within a population. A high value means that allele is common. A low value means it is rare. These values help compare groups across time, place, or treatment conditions. They also support carrier estimates for recessive traits.
Hardy-Weinberg Review
The calculator also compares observed genotype counts with expected counts. The expected values come from Hardy-Weinberg proportions. These are p squared, two pq, and q squared. The chi-square value gives a simple balance check. The p-value is approximate. It is best used as a guide, not as final proof.
Advanced Output Details
The result includes p and q frequencies, allele counts, expected genotype counts, heterozygosity, and an F index. Observed heterozygosity measures the actual heterozygote share. Expected heterozygosity shows the predicted share under random mating. The F index can suggest excess or shortage of heterozygotes.
Practical Use
This calculator is helpful when a teacher, student, or researcher needs quick results. It also creates downloadable files. CSV output works well for spreadsheet analysis. PDF output gives a simple report for records. Always check that genotype counts are reliable before interpreting results.
FAQs
What is allele frequency?
Allele frequency is the proportion of one allele among all alleles at a gene location in a sample or population.
What do p and q mean?
p usually represents the frequency of the first allele. q represents the frequency of the second allele. For two alleles, p plus q equals one.
Can I use genotype counts only?
Yes. This tool is designed for AA, Aa, and aa genotype counts. It calculates allele counts directly from those values.
What is Hardy-Weinberg balance?
It is a model that predicts genotype frequencies from allele frequencies when mating is random and other assumptions are met.
What does expected heterozygosity mean?
Expected heterozygosity is the predicted proportion of heterozygous individuals. For two alleles, it is calculated as 2pq.
What does the F index show?
The F index compares observed and expected heterozygosity. Positive values may suggest fewer heterozygotes than expected.
Is the p-value exact?
No. The p-value is an approximation for a simple one degree freedom chi-square check. Use advanced software for formal research.
Can I export the result?
Yes. Use the CSV button for spreadsheets. Use the PDF button for a simple printable result report.