Humans nearly wiped out 70,000 years ago - RC Groups
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Apr 26, 2008, 05:50 AM
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Humans nearly wiped out 70,000 years ago


http://edition.cnn.com/2008/TECH/04/....ap/index.html

...a National Geographic/Stanford U. study on mitochondrial DNA, indicates numbers may have fallen to 2,000 before recovering to current levels
Apr 26, 2008, 10:11 AM
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I read recently that people who have blue eyes are all related....apparently brown eyes are the "norm", and blue eyes can by traced to a genetic defect in one person, and the defect spread from there.
Apr 26, 2008, 10:23 AM
fix-it-up chappie
tolladay's Avatar
Quote:
Originally Posted by Usta Bee
I read recently that people who have blue eyes are all related....apparently brown eyes are the "norm", and blue eyes can by traced to a genetic defect in one person, and the defect spread from there.
So now I'm defective?
Apr 26, 2008, 10:42 AM
Trons and Fumes
wrightme's Avatar
Quote:
Originally Posted by tolladay
So now I'm defective?
Me too! I wonder if there is a 12-step program.....

"Hi, I am Dave, and I have blue eyes......"
Apr 26, 2008, 11:04 AM
Registered User
The Other Dave's Avatar
Quote:
Originally Posted by tolladay
So now I'm defective?
Well it didn't start now

Oh and I'm apparently defective as well....although my eyes are grey not blue....
Apr 26, 2008, 11:18 AM
Tu ne cede malis
MtnGoat's Avatar
Quote:
Originally Posted by tolladay
So now I'm defective?
Not by a long shot. This progression shows us to be Rev 2.0.
Apr 26, 2008, 11:34 AM
fix-it-up chappie
tolladay's Avatar
Quote:
Originally Posted by MtnGoat
Not by a long shot. This progression shows us to be Rev 2.0.
So it's a feature, not a bug? Cool.
Apr 26, 2008, 12:09 PM
AustinTatious
AustinTatious's Avatar
I may be defective....

My eyes are ... uhh, well its difficult to say . I like to trick people. They look blue and green with Golden speckles in them.. pretty weird.
Apr 26, 2008, 12:13 PM
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Bilbobaker's Avatar
What about people like me who have freckles and red hair?
Apr 26, 2008, 12:18 PM
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Quote:
Originally Posted by Bilbobaker
What about people like me who have freckles and red hair?

You're the stepchildren of the genetic world....you need to be beaten.
Apr 26, 2008, 12:20 PM
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http://www.msnbc.msn.com/id/22934464/



Quote:
People with blue eyes have a single, common ancestor, according to new research.

A team of scientists has tracked down a genetic mutation that leads to blue eyes. The mutation occurred between 6,000 and 10,000 years ago, so before then, there were no blue eyes.

"Originally, we all had brown eyes," said Hans Eiberg from the Department of Cellular and Molecular Medicine at the University of Copenhagen.



The mutation affected the so-called OCA2 gene, which is involved in the production of melanin, the pigment that gives color to our hair, eyes and skin.

"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," Eiberg said.

The genetic switch is located in the gene adjacent to OCA2 and rather than completely turning off the gene, the switch limits its action, which reduces the production of melanin in the iris. In effect, the turned-down switch diluted brown eyes to blue.

If the OCA2 gene had been completely shut down, our hair, eyes and skin would be melanin-less, a condition known as albinism.

"It's exactly what I sort of expected to see from what we know about selection around this area," said John Hawks of the University of Wisconsin-Madison, referring to the study results regarding the OCA2 gene. Hawks was not involved in the current study.

Baby blues
Eiberg and his team examined DNA from mitochondria, the cells' energy-making structures, of blue-eyed individuals in countries including Jordan, Denmark and Turkey. This genetic material comes from females, so it can trace maternal lineages.

They specifically looked at sequences of DNA on the OCA2 gene and the genetic mutation associated with turning down melanin production.

Over the course of several generations, segments of ancestral DNA get shuffled so that individuals have varying sequences. Some of these segments, however, that haven't been reshuffled are called haplotypes. If a group of individuals shares long haplotypes, that means the sequence arose relatively recently in our human ancestors. The DNA sequence didn't have enough time to get mixed up.

"What they were able to show is that the people who have blue eyes in Denmark, as far as Jordan, these people all have this same haplotype, they all have exactly the same gene changes that are all linked to this one mutation that makes eyes blue," Hawks said in a telephone interview.

Melanin switch
The mutation is what regulates the OCA2 switch for melanin production. And depending on the amount of melanin in the iris, a person can end up with eye color ranging from brown to green. Brown-eyed individuals have considerable individual variation in the area of their DNA that controls melanin production. But they found that blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes.

"Out of 800 persons we have only found one person which didn't fit but his eye color was blue with a single brown spot," Eiberg told LiveScience, referring to the finding that blue-eyed individuals all had the same sequence of DNA linked with melanin production.



"From this we can conclude that all blue-eyed individuals are linked to the same ancestor," Eiberg said. "They have all inherited the same switch at exactly the same spot in their DNA." Eiberg and his colleagues detailed their study in the Jan. 3 online edition of the journal Human Genetics.

That genetic switch somehow spread throughout Europe and now other parts of the world.

"The question really is, 'Why did we go from having nobody on Earth with blue eyes 10,000 years ago to having 20 or 40 percent of Europeans having blue eyes now?" Hawks said. "This gene does something good for people. It makes them have more kids."




http://youtube.com/watch?v=bwq9BGRYrP0&feature=related
Last edited by Usta Bee; Apr 26, 2008 at 12:26 PM.
Apr 26, 2008, 12:27 PM
Alarm Bells Softening!
Big Foot 48's Avatar
No, it was two people, 6,000 years ago! I have this book right here that proves it! Silly scientists, when will they ever just give it up?
Apr 26, 2008, 12:35 PM
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My great great grandfather ..Hugh G. Barker.
Apr 26, 2008, 12:38 PM
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Quote:
Originally Posted by Eljimb0
My great great grandfather ..Hugh G. Barker.

Do you have to turn around in a circle three times before you go to bed at night ?.
Apr 26, 2008, 12:43 PM
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Only when the bed is rumpled up...


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