Blue Eyed Gene Comes from a Single Common Ancestor
It turns out that all of us with blue eyes inherited this mutation through a single common ancestor. Scientists were able to derive this from the small degrees of variation within blue eyed individuals and the pigmentation of their eyes.
Alex Barson /
It turns out that all of us with blue eyes inherited this mutation through a single common ancestor. Scientists were able to derive this from the small degrees of variation within blue eyed individuals and the pigmentation of their eyes.
As a result, it is thought to be true that a 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." [1] The ancestor, who carried a "switch" that some inherited, "turns off" melanin production of the iris and results in blue eyes.
What is interesting about this mutation, beyond deriving from a singular ancestor, is that the findings bear neither good nor bad news, only affect the amount of pigmentation that determines the color of one's eyes. There are no benefits or detriments to any shade of eye color and it turns out it is the pigmentation, or the lack thereof, that make us so unique.
Source:
[1] University of Copenhagen. "Blue-eyed humans have a single, common ancestor." ScienceDaily. ScienceDaily, 31 January 2008. <www.sciencedaily.com/releases/2008/01/080130170343.htm>.