Blue Eyed People Can Be Traced to One Ancestor

Despite only being present in roughly 10% of the population, blue eyes are the second most prevalent eye color worldwide. Scientists have been able to track the color's genetic mutation all the way back to a single common ancestor who lived between 6,000 and 10,000 years ago. There were only those with brown eyes back then. The 10% of people with blue eyes who are alive today have inherited a mutation in a particular gene that determines eye color from one person.

The brown allele was turned off in the affected person and their ancestors as a result of the gene mutation. In essence, the choice for brown eyes was eliminated because the mutation reduces the body's capacity to manufacture melanin. As a result, brown eyes cannot fully develop and are replaced by blue eyes. The mutation has no genetic advantage but also no disadvantage, and it appears to be one of those chance events that happens randomly in nature.