Everyone with ordinary inherited blue eyes appears to share a common ancestor, probably someone who lived around 6,000 to 10,000 years ago, when a tiny genetic switch near the OCA2 gene reduced brown pigment in the iris — meaning blue eyes, as we know them today, may trace back to one ancient mutation.

A 2008 study led by Hans Eiberg found that blue-eyed people across distant populations share the same DNA around a switch in the HERC2 gene that dials down OCA2 and reduces iris melanin, the fingerprint of a single founder mutation perhaps 6,000 to 10,000 years old. The finding, and its caveats. The post Everyone with ordinary inherited blue eyes appears to share a common ancestor, probably someone who lived around 6,000 to 10,000 years ago, when a tiny genetic switch near the OCA2 gene reduced