Whilst there are several characteristics that make all of us unique, from the colour of our hair to our shoe size, there’s one characteristic that gives those who share it a lot more in common than you may think – blue eyes!
Naturally, we know that blue eyes are much rarer than brown after scientists revealed that the genetic mutation of the OCA2 gene came from a singular human being many, many years ago.
Researchers have tried hard to understand the peculiar eye colour, studying the OCA2 gene which determines the level of brown pigment in the human eye. And more recently, they discovered that blue eyes actually come from a whole other gene called HERC2, which turns off the OCA2 and reveals the blue pigment.
And since every blue-eyed human being has this exact same mutation, everyone who has blue eyes shares a common ancestor born between 6,000 and 10,000 years ago!
Although there’s more research to be done, it’s thought that this mutation could have spread when humans migrated from Africa to Europe, which would help explain why only people of European descent have blue eyes.
This discovery was made by a research team from the University of Copenhagen, and the author of the study, Professor Hans Eiberg had shared, “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.”
As for green-eyed people, the pigmentation can be explained due to a reduced amount of melanin in the iris, which differs from blue eyes.
Professor Eiberg concluded, ‘From this, we can conclude 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,’.