giovedì 11 febbraio 2010

QUANDO NON C'ERA SPAZIO PER LE PAROLE SCRITTE

E' una parentesi che spero mi venga eprdonata. Non ha niente a che vedere con la letteratura, anzi i fatti che vengono raccontati sono accaduti prima di ogni letteratura, in un luogo che è come una pagina bianca. Fredda, tutta da tracciare...

DA AFP

Go east, young man: Greenland was colonised by Siberians
By Richard Ingham (


PARIS — Hair preserved in permafrost for 4,000 years has shed light on a tribe of Stone Age hunters who crossed from Siberia to Greenland in an unsung odyssey of migration, scientists said on Wednesday.

Unearthed at a site in western Greenland, the hair provides a vivid portrait of a man who died four millennia ago and overturns a mainstream theory about how humans colonised the Arctic New World, they said.

Greenland's first known settlers were not Inuit or Native Americans as widely believed, but the direct descendants of Siberians who somehow crossed the Bering Strait to Alaska and then headed east, according to their report, published by Nature.

The tuft of hair and four pieces of bone, uncovered at Qeqertasussuk, are the only human remains ever found of Saqqaq culture, an enigmatic coastal-dwelling community that lived in western Greenland for some 1,700 years.

Living on harp seals and fish and other marine food, the culture petered out around 800 BC, although the dates are uncertain.

University of Copenhagen researcher Eske Willerslev led a team that exhaustively analysed the precious Qeqertasussuk find.

They teased out nearly 80 percent of the genetic code and identified 353,151 single variations in DNA that are telltale signs of body characteristics.

"What we can see from the genomic data is a number of traits," Willerslev told journalists in a teleconference.

"For example, we can see the guy had most likely brown eyes, brown skin, he had shovel-form front teeth and he had dry earwax, which increased the chance of getting infection in the ear," said Willerslev.

"We can also see that he had a tendency to baldness and because we found quite a lot of hair from this guy we presume he actually died quite young, and we can see he was genetically adapted to cold temperatures, living in the Arctic."

Yet the most surprising find came when the man's genome was matched against those of people alive today.

His closest contemporaries are from Arctic eastern Siberia: ethnic groups called the Chukchis, the Koryaks and Naganasans -- a finding also bolstered by a similar A+ blood group.

Anthropologists have long surmised that the first settlers to North America had either walked across the strait while it was iced over during the winter months, or crossed it by boat, perhaps using the Aleutian islands as stepping stones.

These pioneers then headed south, with their descendants eventually arriving in the southern tip of South America thousands of years later.

Until now, Greenland was believed to have been settled by populations that headed there after prolonged settlement in the New World, such as Na-Dene people of North America, or the Inuit of the Arctic.

Willerslev, though, said that the Saqqaq man could be traced to Siberian peoples who had lived 200 generations before.

"It suggests an independent migration or expansion, if you wish, into the New World from the Old World some 5,500 years ago," he said.

As to why the group should head towards Greenland, where it is permanently cold, rather than balmier climes farther south "is a good question," he said.

It could be that more favourable lands for settlement were already occupied by rivals, or perhaps they were used to Arctic hardship," said Willerslev. "There's no clear answer to it."

The research builds on breakthrough work using mammoth fibres, enabling hair to be used as source of DNA in ancient tissues.

Previous DNA studies have focussed on flesh preserved in mummies or in permafrost, but such samples are liable to contamination by fungi or bacteria.

As a result, a whole array of potential hair samples -- such as from South American mummies or aboriginal hair in museum collections -- could be made to talk, provided potential DNA contamination can be filtered out.

"I won't say it will become routine, but with the prices for (gene) sequencing dropping... I think it will be something that we will see much more (of) in the coming five years," he said.