Blue-eyed folks, take notice: it turns out that you all sprang from the same ancestor.
According to what little we learned from our Additional Science GCSE, blue eyes are a recessive gene, which means that two of them are required for the color to show apparently.
However, if you were curious about the precise origin of these genes, one study has discovered that they can all be linked to an individual.
We are aware that people with blue eyes are far less common than those with brown eyes; according to Heathline, 8–10% of people worldwide have blue eyes.
Now that researchers have discovered that the genetic mutation originated from a single human who lived between 6,000 and 10,000 years ago.
In an effort to establish what changed to result in this transformation, the OCA2 gene, which controls the amount of brown pigment in the human eye, has been extensively studied by scientists.
It turns out that a completely separate 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 determine that everyone stems from a single ancestor? because everyone with blue eyes has the same genetic mutation.
Though much more research is needed, it’s believed that the mutation may have spread as people moved from Africa to Europe. If so, that would help explain why it appears that people of European descent primarily have blue eyes.
The study also examined the variance in less frequent eye colors, like green, which supported the theory that the blue-eyed gene originated from a single person.
According to Professor Hans Eiberg, the study’s author and chair of the Department of Cellular and Molecular Medicine, “Meanwhile, people who have green eyes can be explained by the fact they have a reduced amount of melanin in the iris, which is very different to those with blue eyes.”
“From this, we can conclude that all blue-eyed individuals are linked to the same ancestor. They have all inherited the same switch at exactly the same spot in their DNA.”
It turns out that green eyes are caused by less melanin in our iris, which is a lot more than we ever heard in science class, and that blue-eyed individuals have a common ancestor.