Scientists have found that every person on Earth with blue eyes can be traced back to a single person.
People with blue eyes should pay attention: it turns out that you all have the same ancestor.
From what we learned in our GCSE Additional Science class, blue eyes are caused by a recessive gene, which means that you need two of them for the color to show.
But if you were curious about where these genes came from, one study found that they can all be traced back to a single person.
We know that people with blue eyes are much less common than people with brown eyes. According to Heathline, only 8–10% of people around the world have blue eyes.
Now that scientists have found out that the genetic change came from a single person who lived between 6,000 and 10,000 years ago, they can figure out how it happened.
Scientists have looked closely at the OCA2 gene, which controls the amount of brown pigment in the human eye, to try to figure out what changed to cause this change.
It turns out that a different gene called HERC2 completely shuts down the OCA2 gene, “diluting” brown eyes into blue, and is responsible for the genetic abnormality that causes blue eyes.
And how do they know that everybody comes from the same person? because all people with blue eyes have the same change in their genes.
Even though a lot more research needs to be done, it seems likely that the mutation spread as people moved from Africa to Europe. If that’s the case, it would help explain why it seems like most people with European roots have blue eyes.
The study also looked at the differences between people with less common eye colors, like green. This supported the idea that the gene for blue eyes came from one person.
The study’s author, Professor Hans Eiberg, who is also the chair of the Department of Cellular and Molecular Medicine, said, “People with green eyes have less melanin in their iris, which is very different from people with blue eyes.”
“Based on this, we can say that everyone with blue eyes has the same ancestor. They all have the same switch in their DNA at the exact same place.
It turns out that green eyes are caused by less melanin in the iris, which is a lot more than we ever learned in science class, and that people with blue eyes are related.