TIL - All Blue-eyed People Have the Same Ancestor
If you've got a blue eyes, say hello to the nearest person who shares the same sapphire irises. There is a big chance he's your distant cousin.
Originally, all people had dark (brown) eyes. In the recent study Dr. Hans Eiberg and a team of researchers from Copenhagen University, tracked down a genetic mutation that lead to mysterious phenomenon of blue eyes.
Mutation took place some time between 6000 and 10000 years ago from the person who probably lived in the Black Sea region. This single mutation is the cause of eye color of all blue-eyed people on the planet. Dr. Eiberg claims that before then, there were no blue eyes.
That means that all blue-eyed people share the same DNA and have the same ancestor. Oldest remains of a person with blue eyes are discovered in the southwest of Spain, and they are 7000 years old.
Mutation process
The gene that was studied by researchers is called OCA2 and it is responsible for production of melanin, pigment that gives color to hair, eyes and skin.
Mutation affected this gene causing limited melanin production in the iris and creation of a "genetic switch" which turned off the ability to produce brown eyes.
For the research needs Dr. Eiberg took DNA from blue-eyed women from different countries including Jordan, Denmark and Turkey. Study showed that women from all countries had the same gene changes, and those changes have origin in a single mutation that happened more than 6000 years ago.
"From this we can conclude that all blue-eyed individuals are linked to the same ancestor," Eiberg said. "They have all inherited the same switch at exactly the same spot in their DNA."
Next obvious question for scientists is how in only 10000 years we went from a situation where not a single person had blue eyes, to a situation where more than twenty percent of Europeans have them. There's a even a theory that those blue ocean eyes flourished because their owners were considered more attractive and found mates more easily. But that might be just a rumor started by some blue-eyed scientist trying to seduce his hot assistant.
In any case, seems like the gene is doing something good for the sapphire-colored people.
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That's an interesting theory. Not sure if I concur but it's interesting. Science is mostly theory - I mean where did they get authoritative data about people with blue eyes from 10,000 years ago? I love the blue eyes in the pictures though :)
Right, it's just a theory, so we can't be certain. But it's an interesting idea. :) Thanks for reading!
Yeah, we do have the same ancestor, but the research is wrong. Our ancestor is named Odin from the lands of fire and ice.
Odin owns ye all
Interesting, for additional reading:
http://genetics.thetech.org/original_news/news76
"Because so many unrelated individuals with blue eyes had the same HERC2 DNA difference, blue eyes might have come from one person with the mutation--a common ancestor. Of course it is important to mention that in only one of the studies did the authors look at anyone outside of Europe. And in that study, only seven people outside of Denmark were studied--a very small sample size. Checking more people from other places might find different ways to end up with blue eyes."
So yeah, small-ish sample sizes but this looks like a pretty decent claim. Strange to think that mutations to HERC2 or OCA2 couldn't have happened independently and lead to blue eyes, probably needs additional sampling, but sure looks like all blue eyed people share a common ancestor.
It was strange to me as well that this kind of gene mutations couldn't have happened independently. I guess we'll have to wait for a study that will involve more people from different parts of the world. Thanks for the comment!
Thank you for the post! I missed this work when it originally came out, so it was a nice opportunity for me to take a look at it.