As you know, most people's eyes are a shade of brown, blue, or green. What you may not know, is how eye color actually develops. Why are your eyes the color that they are? Why do some people's eyes seem to change color on a daily basis? Here is everything that you have always wanted to know about eye color.
Why babies are born with blue eyes
While not all babies are born with blue eyes, most babies are. Melanin is the pigment found in the body that darkens eyes, hair, and skin. Therefore, people with dark hair, skin, and eyes, have much more melanin present in their body than people who don't. Most babies don't have much melanin in their bodies at birth. As most babies age, the melanin inside of their bodies increases, changing their eye color.
How different eye colors are formed
Brown eyes are a dominant genetic trait that makes up 55% of the world's population. In fact, scientists believe that at one point, all humans had brown eyes. It wasn't until a genetic mutation caused a lack of melanin and lipochrome that people began to develop different colored eyes. Since having blue eyes is a result of less melanin in the body, where do other eye colors come from?
The reason why eyes with less melanin appear blue is because of the way light is reflected in the eye, due to the scattered pigmentation. Blue eyes are a result of having low melanin (brown pigment) and lipochrome (gold pigment) in their eyes. All blue-eyed people are said to have one common ancestor who first had the genetic mutation. Now, more than 300 million people carry the gene.
Green eyes are much less common. Only an estimated 2% of people in the entire world have green eyes. People with green eyes lack melanin, but not the lipochrome in their eyes. The gold pigmentation causes the eyes to appear green instead of blue as the light reflects off the iris.
People with hazel eyes don't have low melanin in the body. They generally have the same amount as people with brown eyes. The difference is with hazel eyes, the melanin builds up around the outside of the iris instead of being scattered throughout it. People with hazel eyes also have the lipochrome pigmentation. The combination of the melanin build up and lipochrome creates a brownish-green appearance. Depending on the lighting, hazel eyes will change appearance from very brown to very green.
Genetics and eye color
Since having brown eyes is a dominant trait, people with brown eyes are likely to have brown-eyed children. However, that's not always the case. You may have brown eyes, but carry the recessive blue-eyed gene from your parents or even grandparents. That recessive gene has a chance to give you a blue-eyed baby. Several genes come into play when it comes to developing eye color. Scientists still don't fully understand how eye color is developed. The combination of several genes developing in utero can create one of several shades of an eye color.
If one parent has brown eyes and one parent has green eyes, the possibilities are nearly endless. The baby may inherit the dominate brown or only the green. The baby also may have a mixture of the two that creates various shades of hazel. A recessive blue-eyed gene can also pull through and everyone in the family may end up with different color eyes.
Eye color, even covered by eyeglasses, is a fascinating thing. Your eye color is all determined by how the genes mix in your body as you develop in utero. The genes will determine how the melanin and lipochrome develops in your body and give you the eye color that you will have for the rest of your life.