tagged w/ human migration
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Keith Urban Performs FREE Show at Dallas Mall.KEITH Urban is delighted he found love with his actress wife Nicole Kidman — because it has inspired his greatest work.Keith Urban Performs FREE Show at Dallas Mall.KEITH Urban is delighted he found love... more
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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 between 6,000 and 10,000 years ago and is the cause of the eye color 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 color 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 color – 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 color, 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.”New research shows that people with blue eyes have a single, common ancestor. A team... more
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Ancient, 8,000-year-old shoes found in a Missouri cave show that fashion in footwear is nothing new and, in fact, is much older than anyone thought. Scientists said that high-tech dating procedures indicate that the shoes are at least 2,000 years older than previously believed.
The shoes were found 40 years ago in the Arnold Research Cave in Missouri, but, due to the mixing of deposits around the shoes at the dig site, researchers were unable to assign an age to them.
Michael O’Brien of the University of Missouri and colleagues at Louisiana State University used an accelerator mass spectrometer to carbon-date the shoes. It dated the oldest shoes at up to 8,300 years old, the researchers reported in a study published in the journal Science.
“I was surprised,” O’Brien said. “I would have guessed 3,000 but not 8,000. I thought it was so outrageous that I took a second sample.”
Most of the shoes were made with fibrous plants that could be woven into a tough fabric used for the top, bottom and sides of the footwear. O’Brien said the most common material was from a yucca-like plant called rattlesnake master. The leaves were dried and shaped into cording that was woven like modern-day espadrilles.
Both sandal and slip-on styles were found There were also comfort innovations. The moccasins were cushioned with grass that functioned “like a Dr. Scholl’s foot pad,” said O’Brien.
“There’s nothing new under the sun,” he said. “Some of these shoes you would swear were made in a Mexican market.”
The shoes were also very durable, he said. Of 35 samples recovered, 20 were complete or nearly complete. Even though the shoes spanned thousands of years, O’Brien said the basic craftsmanship was about the same.
“They did not invent something flimsy that then got better over time,” said O’Brien. “The earliest shoe is every bit as well-made and as complex as those from later on.”
‘They wore the heck out of these things’
O’Brien said the variety of styles and differences in details suggests that there may have been concessions to style or fashion. “There was no ornamentation or color that we know about, but my guess is that these shoes were very stylish for the time,” he said. “We know that people then were wearing jewelry,” and that it was likely that such artistic interest carried over into the footgear.
Only the moccasins were made of leather, and O’Brien said it is likely that the cave dwellers did not use leather for shoes much earlier than that. The style and construction of the Missouri shoes are similar to specimens unearthed from a nearby site in the Ozark Mountains but are different from shoes found in caves in Kentucky. They are also very different from shoes constructed by the Anasazi people who inhabited Southwest deserts.
Footwear got hard use among the prehistoric Americans. They had to walk most places since there were no horses. They had to hunt or gather all of their food and to haul water back to the cave — all jobs that took much walking. “Many of the shoes wore down exactly the way that our shoes do — the ball of the foot and the heel,” said O’Brien. “In some instances there were repairs where they wove fiber back into them. Other shoes were just tossed, but they wore the heck out of these things.”
"A woman’s 8 1/2 foot size," he said, appears to be much like that of modern humans. There is no way to tell if wearers of the ancient shoes were male or female, but the average length was about 10 1/2 inches — about an 8 1/2 in modern American women’s sizes.
“That suggests that these people fell within the size range of people today,” he said. The cave, which is in a bluff not far from the Missouri River, was a spectacular home by the standards of the time.
“It was really perfect,” said O’Brien. “A great place to live.” O’Brien said that people lived there for hundreds of generations, leaving layer after layer of debris: bone and stone tools, animal bones, char from campfires and even some human remains.Ancient, 8,000-year-old shoes found in a Missouri cave show that fashion in footwear... more
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