PSOR

Biology

Punnett Square Offspring Rate Calculator

Calculate AA, Aa, and aa rates, expected counts, and penetrance-adjusted phenotype references from entered gamete shares.

Parent A dominant-allele gamete share (%)Parent B dominant-allele gamete share (%)Planned offspring observationsEntered dominant-genotype penetrance (%)Entered recessive-genotype penetrance (%)

Parent A recessive gamete share-

Parent B recessive gamete share-

Expected AA rate-

Expected Aa rate-

Expected aa rate-

Expected AA observations-

Expected Aa observations-

Expected aa observations-

Penetrance-adjusted dominant phenotype reference-

Penetrance-adjusted recessive phenotype reference-

Decision view

Punnett square and genotype composition

Punnett square and genotype compositionThe four gamete pairings form a 2×2 matrix and reconcile to the AA, Aa, and aa marginal distribution.

Exact scenario comparisonParent A dominant-allele gamete share (%) changes while all other entered assumptions remain constant.

Parent A dominant-allele gamete share (%)	Parent A recessive gamete share	Parent B recessive gamete share	Expected AA rate	Expected Aa rate	Expected aa rate	Expected AA observations	Expected Aa observations	Expected aa observations	Penetrance-adjusted dominant phenotype reference	Penetrance-adjusted recessive phenotype reference

How to use Punnett Square Offspring Rate Calculator

Enter each parent's dominant-allele gamete share.
Enter planned observations and penetrance references.
Inspect the four-cell square and combined genotype distribution.

Calculator guide

Understanding Punnett Square Offspring Rate Calculator

A Punnett model multiplies the two parents' gamete allele shares to produce mutually exclusive offspring genotype rates.

Complete gamete shares Each parent's two allele shares sum to 100%.

Calculate AA Both gametes contribute the dominant allele.

Calculate Aa Both dominant-recessive orientations create heterozygotes.

Calculate aa The three genotype classes exhaust the model.

Calculation method

How the calculation works

Multiply the two parents' entered gamete allele shares to obtain the three offspring genotype rates and expected counts, then apply separate penetrance references. Complete both parents' allele complements, multiply the four gamete pairings, combine the two heterozygous cells, and apply penetrance.

Detailed calculation process

Build a quantitative two-allele Punnett square

The default gives each parent 50% dominant-allele gametes, projects 100 observations, and uses 100% penetrance references.

General formula: q_A = 100-p_Aq_B = 100-p_BP_AA = p_Ap_B/100P_Aa = (p_Aq_B+q_Ap_B)/100P_aa = q_Aq_B/100E_g = NP_g/100P_dom = (P_AA+P_Aa)d/100P_rec = P_aa r/100 Each of the four Punnett cells is one product of parental gamete shares. The two mixed cells combine into the heterozygous rate.

What each symbol means

p_A, p_B Dominant-allele gamete shares for parents A and B (%).

q_A, q_B Recessive-allele gamete shares (%).

P_AA, P_Aa, P_aa Offspring genotype rates (%).

N Planned offspring observations (count).

d, r Entered dominant and recessive penetrance references (%).

E_g Expected observations of genotype g (count).

Worked substitution with the default inputs

1. Complete gamete shares q_A = 100-50 = 50%q_B = 100-50 = 50% Each parent's two allele shares sum to 100%.

2. Calculate AA P_AA = 50(50)/100 = 25% Both gametes contribute the dominant allele.

3. Calculate Aa P_Aa = [50(50)+50(50)]/100 = 50% Both dominant-recessive orientations create heterozygotes.

4. Calculate aa P_aa = 50(50)/100 = 25%Sum = 25+50+25 = 100% The three genotype classes exhaust the model.

5. Convert to counts and phenotype references E_AA = 25E_Aa = 50E_aa = 25P_dom = 75%P_rec = 25% Expected counts scale the rates to 100 observations.

The default 1:2:1 genotype distribution gives 25 AA, 50 Aa, and 25 aa expected observations.

Purpose-built visual

Punnett square with marginal genotype bars

The 2×2 matrix shows all gamete pairings and the adjacent stack reconciles AA, Aa, and aa to 100%.

Live The visual is regenerated from the current inputs.

Units Counts, money, force, concentration, mass, and percentages retain their stated units.

Check The plotted values reconcile to the displayed calculation.

Worked situations

Practical examples

The default gives each parent 50% dominant-allele gametes, projects 100 observations, and uses 100% penetrance references.
The default 1:2:1 genotype distribution gives 25 AA, 50 Aa, and 25 aa expected observations.

Better inputs

Useful tips

Change one input at a time and confirm that both the results and visual update.
Keep every input in the unit printed beside it.
Retain intermediate precision and round only the reported result.

Before relying on the result

Limitations and common mistakes

This is a single-locus two-allele model.
Linkage, epistasis, selection, sex linkage, mutation, sampling variation, and pedigree uncertainty are excluded.
Expected counts are not guaranteed outcomes.

Reference

Key terms

Gamete share: Probability that a parental gamete carries an allele.
Heterozygous: Genotype containing one dominant and one recessive allele.
Penetrance: Entered share of a genotype class expressed in the phenotype reference.

Important note

Calculated from the entered values using the displayed biological or statistical model. Study design, sampling, measurement quality, and biological variation affect interpretation.

Frequently asked questions

Why are there two Aa cells?

Either parent can contribute the dominant allele.

Must genotype rates sum to 100%?

Yes.

Are expected counts exact predictions?

No.

Does this model handle linked genes?

No.