We so often take for granted the color of our eyes. Whether our eyes are brown, blue or green, we see this as a cosmetic difference and nothing more. We just assume that those with blue eyes have always been around and populated the world as densely as those with other eye colors. Basically, we just take it for granted. But have you ever wondered why our eyes have different colors?
It may surprise you to know that the human race all started out with the same eye color, brown. The differences in eye color came from variances, and in some extremes, such as the color blue, a single mutation was involved.
According to a study published in 2008, everyone with blue eyes has the exact same ancestor from over 7 thousand years ago, who was born somewhere in the black sea region with the mutation.
Professor Hans Eiberg from the Department of Cellular and Molecular Medicine at the University of Copenhagen states, “A genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a “switch,” which literally “turned off” the ability to produce brown eyes.”
Professor Eiberg, through exhaustive study from the year 1996, traveled to areas of the world like Turkey, Jordan and Denmark, to study the eye color blue. Through this study of the mitochondrial DNA, the professor discovered the location of the gene for eye color.
The OCA2 gene is programmed to produce melanin, which is responsible for hair and skin color, as well as eye color. The “switch” is located adjacent to the OCA2 gene and actually only inhibits the melanin producing abilities to a small extent, thus creating the blue eyes instead of an area completely void of melanin.
When melanin is completely absent, the human being experiences albino characteristics.
Taking a closer look at this process enables us to understand why the eye color blue is derived from one ancestor. Since this eye color comes from an exact variance in melanin, it is considered to be a marker passed from a single ancestor. In individuals with green or hazel eyes, the color variances are more random in change and cannot be pinned down to a single occurrence.
The eye color blue did indeed originate from one genetic mutation. However, there are no indications that the differences in our eye color have anything to do with our health or performance in life. In the past, these genes played no part in our ability to survive, unless it was derived from fear or dislike by others.
No matter what our blue-eyed ancestor had to endure, it is clear that the mutation survived and proves just how incredible nature is at shuffling our genes to create something entirely different, and just as beautiful.