“Behind Blue Eyes,” “It’s Blue Eyes Blue,” “Don’t Make My Brown Eyes Blue”; baby blues have long been a popular reference in pop music, but they’re actually a genetic mutation. A team at the University of Copenhagen have revealed a genetic mutation that took place 6-10,000 years ago and is responsible for everyone on the planet today with blue eyes. The Copenhagen team tested 155 people from Scandinavia, Turkey, Jordan and India with blue eyes, to see if they had similar DNA sequences in that gene. Their DNA sequences weren’t simply similar, they were identical.
The mutation of brown eyes to blue isn’t a negative mutation, but rather one of several mutations such as hair color, baldness or freckles; it neither aids nor harms a human’s chances of survival. It’s just a physical quirk that’s popped up over time. Nature is constantly tinkering with the human genome and blue eyes just happen to be one variation of the genetic cocktail of human chromosomes. Though, they might make you more appealing to the opposite sex depending on personal preference.
“Originally, we all had brown eyes,” said Professor Hans Eiberg from the Department 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.”
Removing the the OCA2 gene completely from a human’s genetic code results in the phenomenon known as albinism – something only found in fewer than five people per 100,000.
Whether or not a person has brown, green, or blue eyes is directly related to the amount of melanin in the iris of our eyes. Based on this, Eiberg and his associates are able to conclude that all blue-eyed people are linked to the same distant ancestor.”They have all inherited the same switch at exactly the same spot in their DNA.” Brown-eyed individuals, by contrast, have considerable individual variation in the area of their DNA that controls melanin production. Based on a 2002 study, about 33.8 percent of the white population born in the United States born between 1936 and 1951 have blue eyes. Worldwide that number is closer to around 300 million.
So, if you have blue eyes, you share a relative – albeit a very distant one – with Courtney Cox, Brad Pitt and David Bowie.