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Post by Duke John on Feb 2, 2008 11:31:51 GMT -5
If you've got blue eyes, shake the hand of the nearest person who shares your azure irises: He or she may be a distant cousin. Danish researchers have concluded that all blue-eyed people share a common ancestor, presumably someone who lived 6,000 to 10,000 years ago. "Originally, we all had brown eyes," Professor Hans Eiberg of the University of Copenhagen said in a press release. "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." That "switch" — a simple change from "A," or adenine, to "G," or guanine, in the DNA — actually sits next to the OCA2 gene, which regulates the pigmentation of our eyes, hair and skin, and hence has only a limiting effect on it. If the mutation had completely deactivated OCA2, all blue-eyed people would be albinos. Eiberg and his team analyzed 155 individuals in a large Danish family, plus several blue-eyed people born in Turkey and Jordan. All blue-eyed subjects had the mutation, and there was very little variation on the genes neighboring it on the chromosome, indicating that the mutation first arose relatively recently. In contrast, most mammals share the "normal" form of the gene. The six-letter sequence is exactly the same among mice, horses, cows, rats, dogs, cats, monkeys, chimpanzees and humans with brown eyes. (No word on what gives Siberian huskies and Siamese cats blue eyes.) Eiberg figures the mutation took place on the northern of the Black Sea, but that's an educated guess, assuming the first blue-eyed humans were among the proto-Indo-Europeans who subsequently spread agriculture into western Europe and later rode horses into Iran and India. Ironically, neither the first person to have the mutation, nor his or her children, would have had blue eyes themselves. Blue eyes are a recessive trait, and the gene must be inherited from both parents. (Green eyes involve a related but different gene, one that is recessive to brown but dominant to blue.) It wasn't until the original mutant's grandchildren or great-grandchildren hooked up — cousin marriage is the norm through most of human history — that the first blue-eyed person appeared. He or she must have looked pretty odd for the Neolithic era. Eiberg stresses that the genetic variation, as the press release puts it, is "neither a positive nor a negative mutation." That's a bit disingenuous, as the mutation also produces greater instance of blond hair (sexually selected for even today) and fair skin, which confers a survival advantage by stimulating greater production of vitamin D in sun-starved northern European countries — exactly where blue eyes are still most prevalent. www.ku.dk/english/news/?content=http://www.ku.dk/english/news/blue-eyes.htmwww.foxnews.com/story/0,2933,327070,00.html
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Post by Emperor AAdmin on Feb 2, 2008 12:38:27 GMT -5
Read this recently as I was scrolling through bellow link digg.com/
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Post by hellboy87 on Feb 2, 2008 12:55:51 GMT -5
this was on MSN.com
very intresting! All blue eyes people share the same ancestor!
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Kanaris
Amicus
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Posts: 9,587
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Post by Kanaris on Feb 2, 2008 17:02:15 GMT -5
Red hair comes from the Neanderthal.... was another study they had.... I think this dna stuff is not completely understood by todays scientists.
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Post by c0gnate on Feb 2, 2008 17:40:06 GMT -5
"Scientist: All Blue-Eyed People Are Related"
It's a pretty safe bet that all people are related, at least those that evolved from the apes.
For those that arrived here from another galaxy, it's too early to tell.
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Post by jerryspringer on Feb 2, 2008 21:03:01 GMT -5
"Scientist: All Blue-Eyed People Are Related" It's a pretty safe bet that all people are related, at least those that evolved from the apes. For those that arrived here from another galaxy, it's too early to tell. Hehe, well you can go even further than that and say that all mammals are related to each other, if you look back in time. Say, what colors do your eyes have, cumnate? Do they happen to have the same color as your sheep? Hmmm...
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Post by c0gnate on Feb 2, 2008 21:49:42 GMT -5
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Post by grksdied4you on Feb 3, 2008 23:47:09 GMT -5
Why is this guy who ran this study so concerned about the eye color of people? His name tells me he may have a problem with Aryans.
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Post by Novi Pazar on Feb 5, 2008 0:34:58 GMT -5
"He or she may be a distant cousin."
Its not definite, it would only apply if we are directly related to an individual who developed this mutation.
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Post by diurpaneus on Feb 5, 2008 3:29:40 GMT -5
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tyson
Amicus
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Post by tyson on Feb 5, 2008 6:39:20 GMT -5
Red hair comes from the Neanderthal.... was another study they had.... . lol, could that explain why red heads are all ugly?
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Post by captainalbania on Feb 12, 2008 0:07:48 GMT -5
That "theory" is garbage, precisely for the following facts.
6000 years is approximately 200 generations. Assuming 500 million carry the gene today, that's an increase of 10% in genetic frequency every generation for 200 generations.
This is what they base their bogus claims on
It's very hard to believe blue eyes could cause such a massive comparative advantage amongst people who are otherwise the same. We don't even know what blue eyes might have as an advantage over brown eyes, so how could they possibly produce a 10% comparative advantage for the entire organism?
This isn't the first time scientists have have made big definitive statements based on questionable math and statistics applied usually to rather small genetic samples. They've already "concluded" that white skin evolved in that same time period, which is way too recent and makes no sense at all.
And another time they also reached a "definitive conclusion" on the evolution of speech based also on statistics applied to a "speech" gene. They said the gene evolved 100,000 years ago, coinciding with the evolution of modern humans. They were so sure of themselves. Well, guess what? Last year Spanish scientists detected this same gene in the dna of a Neanderthal fossil, which means the gene has existed for at least 500,000 years, who knows, maybe for a million.
Any genetic age estimates based on gene diversity should be considered stretching the truth. It's way too soon in our genetics knowledge to be making estimations like this.
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donnie
Senior Moderator
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Post by donnie on Feb 12, 2008 18:56:00 GMT -5
Interesting input CaptainAlbania.
Well, personally, I don't think blue eyes evolved on their own, meaning separately from light skin and blonde hair. Because alone, they're not so advantageous, being that light(er) eyes are less protective against sun rays. However, in territories where D-vitamine was poor in the local diet, e.g. Northern Europe, the evolution of lighter pigmentation through the loss of melanin was important. This because sun rays provide D-vitamine, and light skin can absorb it whereas darker skin cannot. The evolution of light pgimentation in more frigid territories was furthermore not so harmful due to the temeperature.
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Post by c0gnate on Feb 12, 2008 19:20:57 GMT -5
This isn't the first time scientists have have made big definitive statements based on questionable math and statistics applied usually to rather small genetic samples. It's not the scientists that are doing that but the media that exaggerates and misrepresents the conclusions published in scientific articles. If you read the articles themselves you'll see that the conclusions are always couched in carefully enumerated and specified caveats, of the form: "If these assumptions are correct, then this follows". The media usually drops the first part. I don't claim that scientific conclusions are always definitive or even correct. Science is anything but definitive. But in order to get the best possible scientific answer at a given time, you need to get it at the source.
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