Eye Color Predictor Calculator
Model eye color inheritance using the two-gene Davenport model. Select the genotypes for both parents to predict the likelihood of blue, green, or brown eyes.
Parent Genotypes
Select eye color genotypes for Mother and Father. (B = Brown, G = Green, b = Blue).
4×4 Eye Color Punnett Grid
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Eye Color Probabilities
Offspring Eye Colors
Genotype Ratios
Melanin Dominance Hierarchy
Brown eyes (high melanin) dominate both Green and Blue. Green eyes dominate Blue (low melanin).
Parental Eye Color Combination Outcome Matrix
| Parent 1 & Parent 2 Phenotypes | Brown Probability (%) | Green Probability (%) | Blue Probability (%) |
|---|---|---|---|
| Brown × Brown (Heterozygous) | 75% | 18.75% | 6.25% |
| Brown × Blue | 50% | 0% | 50% |
| Green × Green (Heterozygous) | 0% | 75% | 25% |
| Blue × Blue | 0% | 0% | 100% |
Calculation Methodology & Biological Principles
The Davenport Model
Bey2 (OCA2 locus) and Gey (HERC2 locus) intet epistatically:
- Bey2 B allele overrides Gey G allele.
- Gey G allele overrides b allele.
Iris Pigmentation Biology
Brown eyes have high concentrations of eumelanin. Green eyes have moderate pheomelanin and Rayleigh scattering. Blue eyes contain minimal melanin pigment.
Frequently Asked Questions
Can two blue-eyed parents have a brown-eyed child? ▼
Under the classical two-gene Davenport model, two blue-eyed parents (bb bb) cannot produce a brown-eyed child because neither carries the dominant B allele. However, rare polygenic modifiers or mutations can occasionally produce brown or hazel highlights.
How does the Davenport two-gene eye color model work? ▼
The Davenport model uses two gene loci: Bey2 (Brown vs. Blue, on chromosome 15) and Gey (Green vs. Blue, on chromosome 19). Brown (B) is dominant over all other alleles. Green (G) is dominant over Blue (b) but recessive to Brown.
Why do some newborn babies' eye colors change after birth? ▼
Human infants are often born with blue or grey eyes because melanocytes in the iris have not yet produced significant melanin pigment. Exposure to light triggers melanin production during the first 6 to 12 months of life, revealing the true genetically determined eye color.
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