An expert has revealed if the theory that every blue-eyed person is a descendant of just one person is true or a myth.
It is estimated that 70-80 percent of the world's general population have brown eyes, while just 8-10 percent have blue eyes and two percent have green.
In fact, according to the American Academy of Ophthalmology (AAO), everyone on Earth had brown eyes until about 10,000 years ago.
So what happened?
I mean, we all come from the same ancestors thousands of years ago, yet people can be born with blue eyes even if their parents don't have them.
It's a very odd phenomenon, but the science behind it is quite fascinating.
You might have heard the theory that everyone with blue eyes is descended from a single ancestor - awkward news for any couples who both have blue eyes, I know - and now an expert has weighed in as to whether this is true.
In a TikTok posted by user @daveallambymd, he reveals that all blue-eyed people are related.
It's because they all descend from one person who lived near the Black Sea 6,000-10,000 year ago.
That person got a mutation in their gene on chromosome 15, which makes brown eyes into blue eyes.
This single recessive gene is the cause of blue eyes.
Dr Allamby continued: "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."
It is odd how just one genetic mutation from thousands of years ago has lasted this long, and spread as wide as it has done where millions carry the recessive gene.
People in the comments shared their thoughts at the confirmation of the theory.
One user said: "Hello brothers and sisters with blue eyes"
Another commented: "Thank the lord I have green eyes and my man has blue."
A third said: "Ok ok all you people with blue eyes, hi fam give me my presents."
A fourth also said: "Y’all forgot my birthday presents."
700 million relatives is quite a lot though, I'd get started on Christmas and birthday presents now just to be safe.
Expanding on the theory, human geneticist Dr Neville Sanjana told Wired it's a little more complicated than saying everyone with a single mutation has blue eyes.
He said: "All current evidence points to an event about 6,000 to 10,000 years ago that resulted in a mutation in a gene called OCA2.
"OCA2 is responsible for a protein called melanin in our eyes. That mutation occurred in Europe and all blue eyed people today are distantly related to that founder from 10,000 years ago.
"But it's not the only gene that's important for eye color.
"There're about eight genes that we know about that contribute to eye color in humans.
"And even if you have the brown eyes version of OCA2, sometimes you can end up with blue eyes. And that's due to the contributions from those seven other genes."Featured Image Credit: Getty Stock Photos and TikTok/@daveallambymd