Blue-eyed people may be surprised to learn that they're all related to one common ancestor, according to a scientific study.
The data comes from a report published by researchers at the University of Copenhagen in Denmark, in which they tracked down a genetic mutation that took place between 6,000-10,000 years ago - and it is this mutation that they say is the cause of the iris color of all blue-eyed humans alive on the planet today.
Professor Hans Eiberg from the university's Department of Cellular and Molecular Medicine said that humans originally all had brown eyes, but that a genetic mutation affecting a gene in our chromosomes resulted in turning off the ability to produce brown eyes in certain people.
GettyImages-691573257.jpgBlue eyes are the result of a genetic mutation. Credit: Cecile Lavabre / Getty
"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," Professor Eiberg said.
The OCA2 gene is involved in the production of melanin, which is the pigment that gives color to our hair, eyes, and skin.
The 'switch' that Professor Eiberg is referring to is located in the gene adjacent to OCA2 (called HERC2) - but he stressed that this does not completely turn off the gene entirely, it only reduces the production of melanin in the iris. This essentially 'dilutes' brown eyes to blue.
GettyImages-142730012.jpgAround 8-10% of people have blue eyes. Credit: Javier Sánchez / Getty
If the OCA2 gene had been completely destroyed or turned off, humans would have no melanin - which is a condition known as albinism.
The researchers eventually found that every blue-eyed person has the exact same mutation in the HERC2 gene.
This theory was confirmed on TikTok by Dr David Allamby, who said in a recent video: "We're all descended from that one person if like me, you've got blue eyes.
"So we've all got more than 700 million relatives."
@daveallambymd Tag your blue eyed friends in the comments 👇👀 #blueeyes #blueeyedpeople #eyefacts #blueeyedfacts #greeneyes #mutation ♬ Love story orchestra - ⚜️
It's possible that the mutation got its start when humans migrated from Africa to Europe, The Independent detailed. This obviously explains why only people with European heritage have blue eyes, and this also means that all blue-eyed people share a common European ancestor.
Dr. Allamby stated that the first individual with blue eyes in believed to have lived near the Black Sea.
Professor Eiberg said in the report that the research into genetic mutation of blue-eyed people "simply shows that nature is constantly shuffling the human genome, creating a genetic cocktail of human chromosomes and trying out different changes as it does so."
Interestingly enough, just 8-10% of the world's population has blue eyes, which are also more sensitive to light.
GettyImages-1134256762.jpgCredit: CoffeeAndMilk / Getty
Yep, that's right. According to Auckland Eye, more melanin in the iris means more protection in the back of the eye from UV radiation and blue light damage. So, given that blue eyes have less melanin than other eye colors, photophobia - or eye discomfort in bright light - is more common in blue eyes.
