Eye Colour is Caused by Melanin Levels
Interestingly, the variation in eye color from brown to green can be explained by the amount of melanin in the iris. Blue-eyed individuals, however, have a limited degree of variation in melanin levels, suggesting a common genetic origin. The research conducted by Professor Eiberg and his team examined mitochondrial DNA and compared the eye color of blue-eyed individuals in countries such as Jordan, Denmark, and Turkey. Their findings support the conclusion that all blue-eyed individuals share a common ancestor.