Saturday, May 08, 2010

Neanderthals Live On in Our DNA...New Study

The most detailed look yet at the Neanderthal genome helps answer one of the most debated questions in anthropology: Did Neanderthals and modern humans mate? The answer is yes, there is at least some cave man biology in most of us. Between 1 per cent and 4 per cent of genes in people from Europe and Asia trace back to Neanderthals.

"They live on, a little bit," says Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Researchers led by Paabo, Richard E. Green of the University of California, Santa Cruz and David Reich of Harvard Medical School compared the genetic material collected from the bones of three Neanderthals with that from five modern humans. Their findings, reported in Friday's edition of the journal Science, show a relationship between Neanderthals and modern people outside Africa, Paabo said. That suggests that interbreeding occurred in the Middle East, where both modern humans and Neanderthals lived side by side thousands of years ago.

The interbreeding probably started when early humans first began to migrate out of Africa.So, people of European, Asian and Australasian origin all have Neanderthal DNA, but not Africans. The study helps resolve the long-running debate over whether Neanderthals and modern humans did more than simply live side by side in these areas.
"Those of us who live outside Africa carry a little Neanderthal DNA in us," said Paabo .
"The proportion of Neanderthal-inherited genetic material is about 1 to 4 percent. It is a small but very real proportion of ancestry in non-Africans today," Dr. David Reich of Harvard Medical School in Boston, who worked on the study, told reporters in a telephone briefing.

While the findings may lead to jokes about cave-man behavior or looks, Paabo said his team cannot identify any Neanderthal "traits."
"As far as we can tell these are just random pieces of DNA," he said.The researchers used modern methods called whole genome sequencing to examine the DNA from Neanderthal bones found in Croatia, Russia, Germany and Spain, including some crushed leg bones from one Croatian cave that some scientists believe are evidence of cannibalism.The researchers developed new methods to gather, distinguish and sequence the Neanderthal DNA.

"In those bones that are 30,000, 40,000 years old there is of course very little DNA preserved," Paabo said. He said 97 percent or more of the DNA extracted was from bacteria and fungi.
The results add to a picture of modern humans living alongside and interacting on the most intimate levels with primitive humans, or, almost humans ,who have now gone extinct.
"It certainly is an indication of what went on socially when Neanderthals and modern humans met," Paabo said.
The DNA sequences date back to somewhere around 80,000 years ago, when modern humans moving through the Middle East on their way out of Africa would have encountered the southernmost populations of Neanderthals.The researchers identified five genes unique to Neanderthals, including three skin genes.
"This suggests that something in the physiology or morphology of the skin has changed in humans," Paabo said.
The closest extinct relative to modern people, Neanderthals existed from about 400,000 years ago to about 30,000 years ago. They coexisted with modern humans for 30,000 to 50,000 years. While many people think of Neanderthals as very primitive, they had tools for things like hunting and sewing, controlled fire, lived in shelters and buried their dead.

In March Paabo and colleagues reported they had found a previously unknown human species that lived 30,000 years ago alongside modern humans and Neanderthals in Siberia.
Scientists have for years speculated that several different species of humans lived side by side at various times over the past million years. But many would have lived in tropical zones where bones are not easily preserved.Paabo said modern-day Africans may carry some of that unknown DNA even if they do not have Neanderthal ancestors.

People are always interested in the questions: Where did I come from? ...How did I get here? We are getting the picture, a bit at a time.
You know those insurance commercials that say,"So easy, even a caveman could do it"? Well, this discovery gives them a whole new meaning.
Here is another interesting question . Should we clone a neanderthal ? it is one of the ideas being bandied about at scientific cocktail parties. The idea is frought with danger.
In the 1920s, the Soviet leader Josef Stalin ordered the researcher who perfected the technique of artificial insemination, Ilya Ivanov, to create a “living war machine. ” Ivanov’s brief, as American writer Charles Siebert reports in his remarkable book, The Wachula Woods Accord, was to artificially inseminate chimpanzees with human sperm to create a new hybrid.Stalin dreamed of a large, invincible Red Army and a vast slave workforce to carry out his Five Year Plans. He thought a chimp-human hybrid would serve admirably. According to Russian newspapers, Stalin told Ivanov “I want a new invincible human being insensitive to pain, resistant and indifferent about the quality of food they eat.”
Ivanov failed miserably to produce such a chimp-human hybrid, though he certainly tried. In the 1930s, the biologist fell from political grace and was exiled to Kazakhstan in one of the many purges of the time.
All this strikes me as an important cautionary tale. What if one of the world’s whacky dictators (and we do have 'em) got it into his head to clone Neanderthals as slave laborers or a new kind of soldier, one physically stronger than modern humans? Far fetched ? Perhaps. But I don’t think we can blithely ignore the lessons of history.

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