New research shows that people with blue eyes have a single, common ancestor. A team at the University in Copenhagen have tracked down a genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blue-eyed humans alive on the planet today. "Originally, we all had brown eyes," said Professor of Cellular and Molecular Medicine.
"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 so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes, and skin. The "switch," which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris -- effectively…