The Biology of Human Eye Color

Do you ever wonder why you look the way you do? The answer to your question is DNA, which stands for Deoxyribose Nucleic Acid. DNA is what determines your hair color, skin color, and any other physical traits you possess.

Although much of your body is pre-determined by DNA, your eye color is not. The color of your eyes is determined by a self-generating liquid called melanin. Melanin is a pigment that is gray, black, or dark brown. The amount of melanin released into your eye is what controls how light or dark your iris may be. If little to no melanin is released into the iris, the colored part of the eye, then you might have blue or green eyes. If a lot is released, then you might have brown eyes.

Eye color within siblings can vary; like with hair, black and brown are the dominant genes. If one child is going to have blue or green eyes it will most likely but not always be the younger one. Although melanin is self-generating, it does become weaker overtime. This is why it is common for elderly people to have lighter eyes. If both parents have brown eyes, unless the kid is albino or some rare case, then it is impossible for the child to have blue eyes. If both parents have blue or green eyes there’s a small chance to that the child will have light brown eyes.

The way you look is because of your DNA inherited from your parents. While other factors may come into play to determine your eye color, have your parents to thank for your eye color.

[Source: Wisconsin State Journal]