Do you share a common ancestor with Ol’ Blue Eyes?

In the news today, a team at the University of Copenhagen team has identified the gene which around 6-10,000 years ago underwent a genetic mutation in one individual who eventually gave rise to all blue-eyed people.

Professor Eiberg from the Department of Cellular and Molecular Medicine explained:

“Originally, we all 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 proof that all blue-eyed people have a common ancestor comes from the fact that whereas eye colours ranging from brown to green are caused by relatively large differences in the amount of melanin in the iris, controlled by “considerable individual variation” in the area of the DNA responsible for melanin production, the variation in iris melanin levels across all blue-eyed individuals is very small. From this Eiberg concluded that all blue-eyed individuals are linked to the same ancestor. They have all inherited the same switch at exactly the same spot in their DNA.

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