SCIENCE in your LIFE
Why Can One Gene Determine the Difference in Eye Color
By K.G.
Have you ever wondered what causes your eye color to be brown, green, or blue? The human genome is a perplex yet amazing aspect to the human body- accounting for every physical and internal trait about yourself! Cool, right? Different eye colors specifically are caused by mutations on a certain gene known as OCA2.
The OCA2 gene is responsible for the production of melanin, which is the pigment that gives your hair, eyes, and skin color. When a mutation occurs, this gene is either turned off completely or limited in its ability to produce.
When limited, the production of melanin in the iris is reduced creating the change from brown eyes to blue. If the gene was completely turned off, that human would not have any melanin production in their hair, eyes, or skin. This would result in a condition known as albinism.
The difference in melanin production between brown and blue eyes isn’t very large. The humans with brown eyes have many variations in melanin production and their DNA compared to one another. Blue eyes, however, are the complete opposite. In order to have blue eyes one must have the genetic mutation in the same exact place on their DNA. This allows scientists to recognize that all blue-eyed individuals are linked to the same ancestor.
Although some genetic mutations can be life threatening, mutations in eye color or hair color don’t put humans at a disadvantage or risk. This study is just proof that the human genome is constantly evolving and changing, giving rise to new traits and characteristics.
Please send any questions or comments to Dr. Spitzer (spitzern@marshall.edu )
Note: Any opinions expressed in these articles are those of the individual authors and do not necessarily represent those of Dr. Spitzer, the Department of Biological Sciences, or Marshall University.