Blue-eyed humans have a single, common ancestor

University of Copenhagen ^ | January 30, 2008 | Unknown

[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 switch’s 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 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.”

[fishtank]

“One data point, does not an extrapolation make, grasshopper, or padawan, or whatever.”

All kidding aside,

there is a lot of hiding of the truth in too much research, I know this first hand. Also, there is far more scientific truth in the Bible than is commonly recognized.

Do you find it in the least curious that the blue-eyed divergence happened at the same time as the explosion of languages from a common root to form the Indo-European langage tree?

[decimon]

Dang, everyone in my family has blue eyes. Aunt, Uncle, cousins. Even my Bro-inlaw and nieces.

How many play the banjo? ;-)

[VRWCmember]

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

Don't it make my brown eyes blue...

[cubreporter]

My mother had dark brown eyes
My father bright blue eyes
My brother and two sisters have dark brown eyes
I have hazel/blue eyes
My husband has bright blue eyes
Our children have bright blue eyes

Our dog has BROWN eyes... :)

What does this all mean???

[VRWCmember]

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

Don't it make my brown eyes blue...

(Not a duplicate post, simply a better picture)

[VRWCmember]

They had a four in one chance of any child having blue eyes.

That's some pretty good odds.

[steveo]

If I swallow anything evil
Put your finger down my throat
If I shiver, please give me a blanket
Keep me warm, let me wear your coat

[decimon]

My mother had dark brown eyes

My father bright blue eyes

My brother and two sisters have dark brown eyes

I have hazel/blue eyes

My husband has bright blue eyes

Our children have bright blue eyes

Our dog has BROWN eyes... :)

What does this all mean???

Does the dog play the banjo?

[VRWCmember]

I tell her that our future children are going to have brown eyes. That's not quite right, is it?

50-50 chance.

[TexasNative2000]

Introducing “Air-Brush Barbie”!

[EggsAckley]

Thank you for the huge belly laugh!

[Paved Paradise]

Mutant Ping back at ya. Mom and Pop have blue eyes - myself and all sibs have blue, all sibs married blue-eyed so all grandchildren are blue also. My son married a brown eyed gal but no kids - so the chain is probably going to be broken.

[Ditter]

My eyes are dark green with reddish brown centers, how did that happen? I am a cur?

[potlatch]

So - my blue eyed son is linked to a different ancestor than me - his green eyed mom?? Lol

[decimon]

My eyes are dark green with reddish brown centers, how did that happen? I am a cur?

Is your mom named Rosemary?

[humblegunner]

There were eight people on the ark, Noah, his wife, the three sons and their wives.

Really?

And what race were they?

[ErnBatavia]

I have blue eyes. My parents have brown eyes

Your parents' secret childhood name for you was "Mailman's Surprise"...

[ryan71]

Blue eyes...Global warming caused it?

[Dubh_Ghlase]

Okay, I'll throw in here:

My Dad had brown eyes, Mom had blue eyes...
both brothers were blond hair and blue eyes!!
me...redhead with green eyes....

My dad had blue eyes, mother had brown eyes...
3 boys, 1 girl....
2 boys had blue eyes and the girl had hazel (blue).
The other boy was brown-eyed...

You sure you're not the red-headed step child, Mr. Farkle?

[brwnsuga]

You mean 1 in 4 chance right.

B b
B BB Bb

b Bb bb

That’s 1 in four.... according to Gregor Mendel’s genetic trait grid thingy.