Sparking a new mystery about early man, Italian scientists have unravelled the DNA of the 5 300-year-old "Iceman" mummy, only to discover that he doesn't appear to have modern descendants anywhere near where he was found in Europe.
The findings add to evidence that humans were constantly going from place to place, even fairly recently in terms of human development, said Jeffrey T. Laitman, director of anatomy and functional morphology at Mount Sinai School of Medicine, in New York City. This is in contrast to theories that suggest humans remained in one place for thousands of years.
"We seem to be a traveling tribe. That's what's coming out from this," said Laitman. "Even our closest ancestors are moving around a bit."
The mummy of the Iceman - also known as "Oetzi" - has fascinated scientists since it was discovered in the Alps in 1991, still frozen in the ice of a glacier. The mummy is remarkably well-preserved: Scientists now know that he was killed - by an arrow in his back followed by a blow with a spiked club to the face - and they suspect he was about 40.
In 2003, researchers reported that the mummy also appeared to have suffered from heart disease, arthritis, degenerative disc disease and a bit of frostbite. Scientists estimate he lived 5 100-5 300 years ago during what's called the Neolithic-Copper Age.
DNA compared to modern Europeans
In the new study, Italian researchers sequenced the mummy's mitochondrial DNA, which is transmitted from mother to child, after taking samples from its intestine. Then they compared the DNA to that from modern Europeans. The findings were published in the Oct. 30 online issue of Current Biology.
The scientists found that the mummy's DNA doesn't match the DNA of modern Europeans. This suggests that while men and women shared the Iceman's genetic heritage at some point in the past, they don't have descendants in Europe now.
"Apparently, this genetic group is no longer present," study co-author Franco Rollo, a researcher at Italy's University of Camerino, said in a university news release. "We don't know whether it is extinct or it has become extremely rare."
The researchers report that the mummy is the oldest human to have had his or her mitochondrial DNA decoded. "What you're looking at really is a little museum of our prehistoric genome," Laitman said. "This is a really great and unique opportunity to look back into the past and see things on a very fine-tuned level that we cannot see just from the bones."
While the study authors don't know for sure why the Iceman's genetic profile has disappeared in Europe, Laitman suspects that human travel is responsible. "We like to move around a lot," he said, and "that has great implications for our understanding of the broader contents of human evolution."
He added that it's important to look at the Iceman in the context of his time, which isn't that far in the past when it comes to human evolution. "They had great societies, communications and the exchange of ideas, all the stuff we have," he said, "except they didn't have writing and the materials that we know." – (HealthDay News, October 2008)
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