Do you have blue eyes? We're related!

[mickeyd]

Blue-Eyed People Have One Common Ancestor
Submitted by News Account on 30 January 2008 - 9:19pm. Genetics
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 color 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 color 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. Therefore the switch’s effect on OCA2 is very specific.
If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin color – a condition known as albinism.


Limited genetic variation
Variation in the color 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 color 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 color.
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 color, baldness, freckles and beauty spots, which neither increases nor reduces a human’s 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.”
Article: Hans Eiberg, Jesper Troelsen, Mette Nielsen, Annemette Mikkelsen, Jonas Mengel-From, Klaus W. Kjaer, Lars Hansen, Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression, Human Genetics, 10.1007/s00439-007-0460-x.
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Blue-Eyed People Have One Common Ancestor | Scientific Blogging

[W2R]

Well hi, cousin!

Interesting article.

[Notmuchlonger]

I have brown eyes. So that means I am full of something.

[Bestwifeever]

You're related to my mother and son but not me....

[growing_older]

I don't think it works that way. Some brown eyed mothers have blue eyed children. Surely they are related.

With recessive and dominant genes for a particular characteristic (eye-color) you may be able to infer a common mutation produced the recessive gene, but that doesn't mean all related individuals display the characteristic. If you have the gene you are theoretically at least distantly related to someone else who has the gene, but you both may be any eye color, depending on what other genes for eye color you each have. Aside from modern genetic tests, the only way to "see" the blue eye gene was that in people with blue eyes you know they have the gene, where in people with brown or green eyes it is uncertain whether they have it (recessive) or not. In other words, if you have blue eyes, you may or may not be related to people with brown eyes and likewise if you have brown eyes you may or may not be related to people with blue eyes. All the common ancestor mutation theory addresses is that If you have blue eye, you are (however distantly) related to the other people with blue eyes.

[lazygood4nothinbum]

Quote:

Originally Posted by mickeyd Blue-Eyed People Have One Common Ancestor Submitted by News Account on 30 January 2008 - 9:19pm....The mutation of brown eyes to blue represents neither a positive nor a negative mutation. It is one of several mutations such as hair color, baldness, freckles and beauty spots, which neither increases nor reduces a human’s chance of survival.

to say blue-eyed people have only one common ancestor assumes the mutation in that gene only occurred once. how do they know it didn't happen in more than one person so many years ago?

based on my own attraction to the combination of brown hair and blue eyes, i'm not convinced it doesn't increase the human chance of survival if hetero's see the same thing i do; as i've noticed it sure does make for a mutation in my genes.

[FinallyRetired]

I always figured that blue eyed people were mutants.

[HFWR]

What about greenish-blue, or is it bluish-green...?

"We're just mutants of this here monster..."

Black Oak Arkansas

[Zipper]

Mother Zipper blue..................Father Zipper brown.

The Zipper and 1 brother blue...1 brother brown.

Mrs. Zipper ...........................green.

#1 son blue............................daughter-in-law brown.

All three grandchildren..............blue.

#2 son blue.