Eye Color Punnett Square Calculator
Enter parent genotypes (e.g., Bb for brown eyes, bb for blue eyes) to predict eye color inheritance in offspring.
Eye Color Punnett Square Calculator
This tool predicts possible eye colors of offspring based on the genotypes of their parents. It uses basic Mendelian genetics to model dominant and recessive allele inheritance, focusing on brown (B) and blue (b) eye color genes. Explore more genetic inheritance tools and study aids on our website.
How the Eye Color Calculator Works
The dominant B allele produces brown eyes, while the recessive b allele results in blue eyes. The possible genotypes and their associated phenotypes are:
- BB – Brown Eyes (Homozygous dominant)
- Bb – Brown Eyes (Heterozygous)
- bb – Blue Eyes (Homozygous recessive)
The calculator cross-matches each allele from one parent with the other to generate all potential offspring genotypes and calculate the probability of each eye color.
Eye Color Inheritance Explained
Eye color is inherited through genes from both parents, primarily involving two key genes: OCA2 and HERC2. These genes control the amount of melanin in the iris:
Brown Eyes (Homozygous) are dominant and require at least one brown allele (BB).
Brown Eyes (Heterozygous) are recessive to brown(Homozygous) but dominant over blue (Bb).
Blue Eyes are recessive and only appear if both alleles are blue (bb).
Each parent passes one allele to the child, and the combination determines the child’s eye color. For example:
- Bb × bb may result in 50% brown and 50% blue eyes.
- Bb × Bb may result in 75% brown and 25% blue eyes.
Although commonly simplified, real eye color inheritance is polygenic, meaning it involves multiple genes, which explains variations like hazel, gray, or mixed shades.
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FAQs – Eye Color Genetics
Is eye color determined by only one gene?
Not in real life. Multiple genes affect eye color, but this calculator models it using a simple one-gene system for educational clarity.
Can two brown-eyed parents have a blue-eyed child?
Yes, if both parents carry the recessive b allele (Bb), there’s a 25% chance of a blue-eyed child.
Is green or hazel eye color supported?
No, this calculator supports only brown and blue eyes using B/b alleles.