Don't It Make Your Brown Eyes Blue?

[♦ nivek ♦]

Don't It Make Your Brown Eyes Blue?

 

http://sciencenow.sciencemag.org/cgi/content/full/2008/201/1

By Elizabeth Quill

ScienceNOW Daily News

1 February 2008

 

 

Blue-eyed? Thank a genetic switch that turns off your body's ability to make brown pigment in your peepers. Researchers have finally located the mutation that causes blue eyes, and the findings suggest that all blue-eyed humans share a single common ancestor born 6000 to 10,000 years ago.

 

Researchers have implicated the OCA2 gene in several eye colors. The gene is involved in the production of melanin, a pigment that gives hair and skin their hues. It also codes for brown eyes and can lead to green or hazel eyes when mutated. Despite years of searching, however, scientists have not found a mutation for blue eyes on the gene.

 

It turns out they were looking in the wrong place. Trying to narrow the site of the mutation, gene mapper Hans Eiberg of the University of Copenhagen and colleagues examined members of a large Danish family, an approach that allowed them to follow DNA as it passed from one generation to another. Then, by comparing people with brown or blue eyes, including people from Jordan and Turkey, the researchers were able to pinpoint the exact mutation. It wasn't on the OCA gene but rather on a nearby gene called HERC2.

 

The mutation works like a switch that regulates the OCA gene, the team reports in the January issue of Human Genetics, turning off the production of brown eye color and allowing blue eyes to shine through. Because blue eye color is found almost exclusively in people of European descent, Eiberg's team speculates that the mutation traces back to the Neolithic expansion, when people in the Black Sea region migrated to northern Europe 6000 to 10,000 years ago.

 

Two other studies, both appearing in this month's issue of The American Journal of Human Genetics, examined blue eyes in different populations and found the same mutation. The researchers also suggested a common ancestor for all blue-eyed individuals. These teams, however, did not estimate an age for the mutation. Geneticist Richard Sturm of the University of Queensland in Brisbane, Australia, an author of one of the papers says that someday scientists may find additional mutations that cause blue eyes but for now, the signs point to a single change.

 

Sturm says that it's not uncommon for one gene to regulate another, but it is difficult to locate the mutation in the controlling gene. One of the most cited examples is the mutation involved in lactose tolerance, which is also caused by regulation from outside the gene. Sturm says that such regulating genes may contribute more to genetic diversity than previously thought.

 

The findings also have applications in forensics. Geneticist Manfred Kayser of the Erasmus University Medical Center in Rotterdam, the Netherlands, an author of the other paper that appears in The American Journal of Human Genetics, says if police fully understood mutations behind eye color, for example, then they could use them to determine the eye color of a suspect based solely on DNA evidence.

 

Geneticist Tony Frudakis of DNAPrint Genomics Inc., a Sarasota, Florida, company that develops genetic-testing products, is shocked that the mutation happened just once. Although there are about 10 ways to get someone with red hair, the scientists found only one way to get someone with blue eyes. "I would have thought blue eyes arose several times independently," Frudakis says.

 

There are still large questions, though. Why did blue eyes persist? Scientists say it is difficult to see how eye color would have an environmental advantage, as skin color does. Some theories suggest that women may have played a role in driving the selection. Perhaps, Kayser says, "the females thought it more exciting to have a male with blue eyes."

[hereticzero]

Aye, matey! Vikings be our common ancestor, not Adam!

[Sophronia]

Actually, donuts are what made my brown eyes blue.

[Grandpa Harley]

Aye, matey! Vikings be our common ancestor, not Adam!

 

did you just feel a noodly appendage?

[mwc]

Aye, matey! Vikings be our common ancestor, not Adam!

O ye of little faith...

15 And the Lord said, Truly, if Cain is put to death, seven lives will be taken for his. And the Lord put a mark on Cain so that no one might put him to death.

Tis Cain that be the blue eyed one ye be seeking. All with the blue eyes be descendants of the wretched Cain (woe be unto myself but it explains the allure of those with the blonde hair, blue eyes and ample bosom).

 

mwc

[Guest Marty]

I was told that god made Cain black. That also explained why they were treated so badly and made slaves, etc.

[Grandpa Harley]

Then how did black folk manage to survive the flood?

[The-Captain]

Then how did black folk manage to survive the flood?

 

Heh good question.

[hereticzero]

Aye, matey! Vikings be our common ancestor, not Adam!

 

did you just feel a noodly appendage?

Aaargh! I did, says I. I'm feelin' like a pastafarian revival. Spaghnostics welcome.

[par4dcourse]

I thought my bleu eyes and translucent whiteness was a curse. Now I'm blessed. Glory.

[hereticzero]

I forgot to mention to click on my upload photo of the Lord's Last Supper to see it magically transform into its true appearance.

[RankStranger]

This means that my wife and I are kissin' cousins... sharing a common ancestor and all.

[woodsmoke]

Yeah, but you live in the south, so it's okay.

[Taphophilia]

It doesn't say if they are lumping blue eyes and gray eyes, which are a bit different. Gray eyes have more melanin than blue.

 

The reason that eyes appear blue is the same reason the sky does. They have very little pigment and it's the way light is refracted.

[Aqua Kitty]

It doesn't say if they are lumping blue eyes and gray eyes, which are a bit different. Gray eyes have more melanin than blue.

 

The reason that eyes appear blue is the same reason the sky does. They have very little pigment and it's the way light is refracted.

 

I wonder if this is similar to coloring in blue birds (which are not blue at all but but grey, but appear blue due to light refraction or something.) Anyway, if you grind up a blue feather, the powder will not be blue, but grey. Whereas if you grind up a red feather, the powder will still be red.

[Skiergirl24]

Don't It Make Your Brown Eyes Blue?

 

http://sciencenow.sciencemag.org/cgi/content/full/2008/201/1

By Elizabeth Quill

ScienceNOW Daily News

1 February 2008

 

 

Blue-eyed? Thank a genetic switch that turns off your body's ability to make brown pigment in your peepers. Researchers have finally located the mutation that causes blue eyes, and the findings suggest that all blue-eyed humans share a single common ancestor born 6000 to 10,000 years ago.

 

Researchers have implicated the OCA2 gene in several eye colors. The gene is involved in the production of melanin, a pigment that gives hair and skin their hues. It also codes for brown eyes and can lead to green or hazel eyes when mutated. Despite years of searching, however, scientists have not found a mutation for blue eyes on the gene.

 

It turns out they were looking in the wrong place. Trying to narrow the site of the mutation, gene mapper Hans Eiberg of the University of Copenhagen and colleagues examined members of a large Danish family, an approach that allowed them to follow DNA as it passed from one generation to another. Then, by comparing people with brown or blue eyes, including people from Jordan and Turkey, the researchers were able to pinpoint the exact mutation. It wasn't on the OCA gene but rather on a nearby gene called HERC2.

 

The mutation works like a switch that regulates the OCA gene, the team reports in the January issue of Human Genetics, turning off the production of brown eye color and allowing blue eyes to shine through. Because blue eye color is found almost exclusively in people of European descent, Eiberg's team speculates that the mutation traces back to the Neolithic expansion, when people in the Black Sea region migrated to northern Europe 6000 to 10,000 years ago.

 

Two other studies, both appearing in this month's issue of The American Journal of Human Genetics, examined blue eyes in different populations and found the same mutation. The researchers also suggested a common ancestor for all blue-eyed individuals. These teams, however, did not estimate an age for the mutation. Geneticist Richard Sturm of the University of Queensland in Brisbane, Australia, an author of one of the papers says that someday scientists may find additional mutations that cause blue eyes but for now, the signs point to a single change.

 

Sturm says that it's not uncommon for one gene to regulate another, but it is difficult to locate the mutation in the controlling gene. One of the most cited examples is the mutation involved in lactose tolerance, which is also caused by regulation from outside the gene. Sturm says that such regulating genes may contribute more to genetic diversity than previously thought.

 

The findings also have applications in forensics. Geneticist Manfred Kayser of the Erasmus University Medical Center in Rotterdam, the Netherlands, an author of the other paper that appears in The American Journal of Human Genetics, says if police fully understood mutations behind eye color, for example, then they could use them to determine the eye color of a suspect based solely on DNA evidence.

 

Geneticist Tony Frudakis of DNAPrint Genomics Inc., a Sarasota, Florida, company that develops genetic-testing products, is shocked that the mutation happened just once. Although there are about 10 ways to get someone with red hair, the scientists found only one way to get someone with blue eyes. "I would have thought blue eyes arose several times independently," Frudakis says.

 

There are still large questions, though. Why did blue eyes persist? Scientists say it is difficult to see how eye color would have an environmental advantage, as skin color does. Some theories suggest that women may have played a role in driving the selection. Perhaps, Kayser says, "the females thought it more exciting to have a male with blue eyes."

 

Blasphemy!!! Don't you know that God planned each and every one of us to be special?

 

"Before I formed you in the womb, I knew you. Before you were born, I set you apart for my holy purpose"-Jeremiah

 

BWAHAHAHAHAHHAHAHAHAHA kidding obviously

[MathGeek]

This means that my wife and I are kissin' cousins... sharing a common ancestor and all.

 

I agree, so am I yet my eyes are green. My mom and two siblings are blue-eyed Nordic descendants.