The Black Sea coast holds some of Europe’s most beautiful, wild, and rugged landscapes (Image: Getty)
Blue eyes have long fascinated humans, symbolising beauty and mystery throughout history. From iconic figures like to stars like Megan Fox, their allure is undeniable. But how did this rare eye colour originate, and why is it so coveted?
A led by Dr Hans Eiberg and his team at the University of Copenhagen has traced all blue-eyed individuals back to a single common ancestor who lived approximately 10,000 years ago in the Black Sea region.
This discovery has shed light on the responsible for blue eyes, offering remarkable insights into human evolution.
Eye colour is determined by the amount of melanin, a pigment, in the iris. Brown eyes, the most common colour, result from high melanin levels, while lighter shades like blue and green occur due to reduced melanin.
Through his research, Dr Eiberg pinpointed a mutation in the OCA2 gene, which regulates melanin production.
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Blue eyes have been coveted for years – scientists may now know why. (Image: Getty)
This mutation didn’t create the blue colour directly but instead acted as a “switch” that limited melanin production in the iris, leading to blue eyes.
“Originally, we all had brown eyes,” Dr. Eiberg explained in his study, published in 2008. “A genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a ‘switch’ that literally turned off the ability to produce brown eyes.”
The most striking aspect of the study was its discovery of the genetic uniformity among blue-eyed individuals. Over 99.5% of those studied share the same tiny mutation, suggesting this change occurred in a single individual. The trait spread across populations from this ancestor, creating the diverse group of blue-eyed people we see today.
The team traced the mutation to the , which encompasses parts of modern-day , , Georgia, Turkey, Romania, and Bulgaria. This period coincided with the spread of agriculture from the Middle East into Europe, a time in which rapid population expansion took place.
The study analysed the DNA of over 800 participants, ranging from fair-skinned Scandinavians to dark-skinned, blue-eyed individuals in Turkey and Jordan. Astonishingly, all but one had identical genetic sequences in the relevant part of the OCA2 gene.
“This strongly indicates that all blue-eyed individuals are linked to the same ancestor,” said Dr. Eiberg. “They have inherited the same switch at exactly the same spot in their DNA.”
While the mutation’s origin is now understood, the reasons for its widespread adoption remain unclear. Some researchers hypothesise that blue eyes may have offered an evolutionary advantage in regions with long summer days and short winter hours, as they could adapt better to varying light conditions.
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Modern-day blue-eyed people can trace their ancestors to somewhere along the Black Sea coast (Image: Getty)
Another theory points to sexual selection, suggesting that the rarity and attractiveness of blue eyes may have made them desirable traits in choosing mates.
The findings highlight how . While blue eyes are rare globally, over time, they became concentrated in northern and eastern Europe, where the mutation likely provided some advantage.
Today, blue eyes are celebrated for their beauty, but for much of human history, they were an evolutionary accident—a random mutation that sparked a cascade of genetic and social changes.
With this in mind, the research not only illuminates the origin of blue eyes but also offers a glimpse into the interconnectedness of human history. The story of blue eyes is a story of migration, adaptation, and the randomness of genetic inheritance.