Genetics Eye Color Calculator

Eye Color Probability Calculator

Brown Blue Green
Brown Blue Green

Child's Predicted Eye Color:

Brown
0%
Blue
0%
Green
0%

How Eye Color Inheritance Works

Eye color is determined by the amount and type of pigments in the iris. While modern science has discovered that eye color is polygenic (influenced by up to 16 different genes), the primary model used for prediction focuses on two major genes: OCA2 and HERC2.

Dominant vs. Recessive Traits

In classical Mendelian genetics, eye color is often explained through dominance. Brown is generally dominant over both green and blue. Green is dominant over blue but recessive to brown. Blue is considered a recessive trait.

  • Brown Allele: Dominant. If you have one brown allele, your eyes will likely be brown.
  • Green Allele: Recessive to brown, dominant to blue.
  • Blue Allele: Recessive. Usually requires two blue alleles to manifest.

Common Inheritance Scenarios

Using our calculator, you can see how different parental combinations result in various statistical outcomes. Here are a few common examples:

Parental Match Statistical Probability
Brown + Brown 75% Brown, 18.75% Green, 6.25% Blue
Blue + Blue 99% Blue, 1% Green, 0% Brown
Green + Green 75% Green, 25% Blue, < 1% Brown

Why Predictors Aren't 100% Accurate

It is important to remember that genetics is complex. Because eye color is polygenic, it is possible for two blue-eyed parents to have a brown-eyed child, though it is extremely rare. Factors like gene mutation, epistasis (one gene masking another), and minor genes can all influence the final phenotype of the child's eyes.

function calculateEyeProbability() { var p1 = document.getElementById("parent1").value; var p2 = document.getElementById("parent2").value; var brown = 0; var blue = 0; var green = 0; // Logic based on standard genetic probability tables (Simplified Davenport Model) if (p1 === "brown" && p2 === "brown") { brown = 75; green = 18.75; blue = 6.25; } else if ((p1 === "brown" && p2 === "blue") || (p1 === "blue" && p2 === "brown")) { brown = 50; green = 0; blue = 50; } else if ((p1 === "brown" && p2 === "green") || (p1 === "green" && p2 === "brown")) { brown = 50; green = 37.5; blue = 12.5; } else if (p1 === "blue" && p2 === "blue") { brown = 0; green = 1; blue = 99; } else if ((p1 === "blue" && p2 === "green") || (p1 === "green" && p2 === "blue")) { brown = 0; green = 50; blue = 50; } else if (p1 === "green" && p2 === "green") { brown = 1; green = 75; blue = 24; } // Display Results document.getElementById("brown-pct").innerHTML = brown.toFixed(1) + "%"; document.getElementById("blue-pct").innerHTML = blue.toFixed(1) + "%"; document.getElementById("green-pct").innerHTML = green.toFixed(1) + "%"; document.getElementById("results-area").style.display = "block"; // Smooth scroll to results document.getElementById("results-area").scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

Leave a Reply

Your email address will not be published. Required fields are marked *