Posted on 01/30/2008 2:10:37 PM PST by 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.”
My granddaughter has blue eyes—both her parents have brown eyes—all her grandparents have brown eyes—it turns out both her maternal great grandmothers had blue eyes—so those recessive blues traveled down through 3 generations before showing up—interesting how that works.
Hence, the stricture against bestiality.
It is impossible, barring mutation, for two blue-eyed parents to have a non-blue eyed baby. (You can sometimes get green, but I can’t remember how.)
(I dealt with paternity with some regularity as a senior enlisted in the Army -— master chief, I think, is the equivalent for squids. The CO would hand this off to me without looking; all sorts of paperwork and sometimes serious ramifications.)
We have four brown and two green in addition to the three with blue eyes. We’re still waiting to see if the youngest blue-eyed one turns out to have green eyes. Our two greens were blue-eyed until around 3 years of age.
My x wife’s eyes are brown. Male bovine manure color.
No it’s not impossible. Just unlikely. But it is definitely possible...
lol
You are correct....ADAM.
I got my paternal grandmother's wedding ring. A much better heirloom, not nearly so messy.
Who cares if the Writer’s Guild is on strike.
The Drowned Continent of Southeast Asia
Stephen Oppenheimer
The biblical flood really did occur - at the end of the last Ice Age. The Flood drowned for ever the huge continetal shelf of Southeast Asia, and caused a population dispersal which fertilized the Neolithic cultures of China, India, Mesopotamia, Egypt and the eastern Mediterranean, thus creating the first civilizations.
The Polynesians did not come from China but from the islands of Southeast Asia. The domestication of rice was not in China but in the Malay Peninsula, 9,000 years ago.
In this ground breaking new book Stephen Oppenheimer reveals how evidence from oceanography, archaeology, linguistics, genetics and folklore overwhelmingly suggests that the lost 'Eden' - the cradle of civilization - was not in the Middle East, as is usually supposed, but in the drowned continent of Southeast Asia.
That has to be David Bowie’s offspring. One brown, one blue eye.....
http://www.usatoday.com/tech/columnist/aprilholladay/2004-10-14-wonderquest_x.htm
Scroll down a little to the question
Gota like a girl with “nasty” tatooed on her.
Right, but his sister or sisters would have been too, since both parents have to have the blue eyed gene to get blue eyed children.
This seems to explain the connection between eye color & sunburn. I've heard that people with blue eyes burn more easily than those with brown eyes, even if those with brown eyes have lighter skin.
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