New research shows that people with blue eyes have a single, common ancestor. A group of scientists at the University of Copenhagen have found a genetic mutation which took place 6-10,000 years ago and is the cause of the eye color of all blue-eyed humans alive on the planet today. They originally said that all humans had brown eyes, but 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. The OCA2 gene codes for the P protein, which is involved in the production of melanin. This switch limits its action to reducing the production of melanin in the iris which is effectively "diluting" brown eyes to blue. The mutation of brown eyes to blue represents neither a positive nor a negative mutation. It simply shows that nature is constantly shuffling the human genome, creating a genetic cocktail of human chromosomes and trying out different changes as it does so.
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