Around eight to ten per cent of the population have blue eyes and apparently, they all have one thing in common.
It’s the second most popular eye colour in the world and the shade is believed to have started around 6,000 to 10,000 years ago.
The widespread iris colouration is believed to have started due to a genetic mutation as, originally, all humans had brown eyes – in different shades.
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Recently, a gene has been identified that causes blue eyes, and it’s called HERC2.
This gene switches off OCA2 – which results in different shades of brown eyes – and it determines the amount of brown pigment melanin that we make.
Professor Hans Eiberg, from the university’s Department of Cellular and Molecular Medicine, explains: “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.”
It is believed to have originally begun when humans first migrated from Africa to Europe, The Independent details.
The study suggests that all blue-eyed people are descendants of one person.
Although it remains a mystery who first started this initial mutant gene, the fact every blue-eyed person has this mutation is pretty compelling evidence.
Professor Eiberg says in the report that the research into the genetic mutation of people with blue eyes ‘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’.
But that’s not the only interesting thing about blue eyes.
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It also has been discovered that blue-eyed people are also more sensitive to light.
If you have more melanin in the iris, it means you have more protection in the back of the eye from UV radiation and blue light damage, as per Auckland Eye.
So as people with blue eyes have less melanin than other colours, photophobia (which means abnormal sensitivity to light) is usually more common.
While this may sound like a negative, there are actually many perks to having blue eyes.
A study, conducted by Louisville University professor Joanna Rowe, has found that people with this eye shade are more likely to be better strategic thinkers, as reported by Daily Mail.
The professor clarifies: “It is just observed rather than explained. There’s no scientific answer yet.”
There are many celebrities with blue eyes who have bright minds, including Stephen Hawking, Alexander Fleming and Marie Curie.