Aside from their blue eyes, all blue-eyed persons have one characteristic.

It is the world’s second most popular eye color, with origins estimated to be between 6,000 and 10,000 years ago.

The widespread iris coloration appears to be the result of a genetic mutation, as all humans originally had brown eyes of varying tints.

There are many additional intriguing facts regarding blue-eyed folks.

For example, they are more sensitive to light; having more melanin in the iris implies having more protection in the back of the eye from UV radiation and blue light damage, according to Auckland Eye.

People with blue eyes have less melanin than other colors, hence photophobia (abnormal sensitivity to light) is more common.

While this may sound bad, there are numerous benefits to having blue eyes.

According to the Daily Mail, a study conducted by Louisville University professor Joanna Rowe discovered that persons with this eye hue are more likely to be better strategic thinkers.

The professor clarifies: “It is simply observed rather than explained.” “There is no scientific answer yet.”

Many famous people with blue eyes have brilliant minds, like Stephen Hawking, Alexander Fleming, and Marie Curie.

Most interestingly, all blue-eyed persons have one trait in common, and the fact has startled many.

Someone writes, “I had no idea! Fascinating…”

Another joke: “Spoiler alert: all of their eyes are blue.”

However, it turns out to be much more intriguing than that (quite obvious) response.

Blue eyes are caused by a gene known as HERC2.

This gene inhibits OCA2, which causes varied hues of brown eyes, and regulates the quantity of brown pigment melanin produced.

Professor Hans Eiberg of the University of Copenhagen’s Department of Cellular and Molecular Medicine explains: “Initially, we all had brown eyes. However, a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the formation of a’switch’ that literally ‘turned off’ the ability to generate brown eyes.”

According to The Independent, it originated when humans first traveled from Africa to Europe.

According to a study conducted at the University of Copenhagen, all blue-eyed people are descended from the same individual.

Although it is unclear who first created this initial mutant gene, the fact that every blue-eyed individual carries it is rather persuasive proof.

According to Professor Eiberg, study into the genetic mutation of persons with blue eyes’simply indicates that nature is continually mixing the human genome, building a genetic cocktail of human chromosomes and testing out new alterations as it does so’.