Skip to comments.Blue-eyed humans have a single, common ancestor
Posted on 01/30/2008 2:10:37 PM PST by decimon
New research shows that people with blue eyes have a single, common ancestor. A team at the University of Copenhagen have tracked down a genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blue-eyed humans alive on the planet today. What is the genetic mutation
Originally, we all had brown eyes, said Professor Eiberg from the Department of Cellular and Molecular Medicine. But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a switch, which literally turned off the ability to produce brown eyes. The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin. The switch, which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris effectively diluting brown eyes to blue. The switchs effect on OCA2 is very specific therefore. If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour a condition known as albinism. Limited genetic variation
Variation in the colour of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes. From this we can conclude that all blue-eyed individuals are linked to the same ancestor, says Professor Eiberg. They have all inherited the same switch at exactly the same spot in their DNA. Brown-eyed individuals, by contrast, have considerable individual variation in the area of their DNA that controls melanin production.
Professor Eiberg and his team examined mitochondrial DNA and compared the eye colour of blue-eyed individuals in countries as diverse as Jordan, Denmark and Turkey. His findings are the latest in a decade of genetic research, which began in 1996, when Professor Eiberg first implicated the OCA2 gene as being responsible for eye colour. Nature shuffles our genes
The mutation of brown eyes to blue represents neither a positive nor a negative mutation. It is one of several mutations such as hair colour, baldness, freckles and beauty spots, which neither increases nor reduces a humans chance of survival. As Professor Eiberg says, it simply shows that nature is constantly shuffling the human genome, creating a genetic cocktail of human chromosomes and trying out different changes as it does so.
Yes, on This Thread:
That is all well and good, but what about green and hazel eyes.
One of the two must be fake.
Here’s some info about Cain’s wife:
And about Noah, although I don’t know if your question is addressed:
It is possible ... I know for a fact.
Were you absent that day from class? Once upon a time, a daddy and a mommy loved each other very much...
That’s it. We need one like that for the Atlantic showing Atlantis morphing into the Bahamas, Hispaniola, Azores and Canary Islands.
Sundaland is probably Atlantis.
So my blue eyes are a gift from Atlantis. I like that. ;-)
There's a mutant in the woodpile.
More seriously, I guess the green and hazel result from mixing the DNA of brown and blue eyed mates. Maybe someone with better knowledge will weigh in.
Noah’s kids were all adopted, So it was sorta ok.
Adam may have had brown eyes, but I believe Eve had green eyes.
LOL! That’s cute!
Ah. I hadn’t considered that.
If that helps you sleep better at night, ok.
Of course the same sort of genetic tests that dated the last common ancestor of blue eyed people also dated the last common ancestor of human beings and chimpanzees as 4.1 million years ago.
What do you think about that?
Dang, everyone in my family has blue eyes. Aunt, Uncle, cousins. Even my Bro-inlaw and nieces.
That's one possibility.
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