(Related: "Siberian, Native American Languages Linked — A First" [March 26, 2008].)
"There would have been populations all the way from Alaska to Greenland, but then the whole thing vanishes and another lot come in," Gilbert said. "A separate, new migration gave rise to the current Inuit."
Archaeological studies link the earliest Eskimos in Greenland to the Saqqaq culture, which appeared some 4,500 years ago, while the later Thule culture arose 1,000 years ago.
Tools associated with the two groups are very different.
For example, Saqqaq hunting equipment is described as "fly fishing tackle" compared to the much later, bulkier equipment, Gilbert said.
"Saqqaq culture is very distinctive, with finely made and precise tools such as lightweight harpoons and small [fishing] hooks," he said.
This archaeological transition in Greenland is now supported by the new DNA evidence, Gilbert added.
Peter Forster, who studies archaeogenetics at Anglia Ruskin University in the United Kingdom, wasn't involved in the new study.
He said consensus among archaeologists had been that "the Paleo-Eskimos probably died out, but there's no means of knowing that for sure."
So this latest finding "makes beautiful sense" and "resolves an ongoing recent discussion in science," Forster said.
The distinct DNA signature of the frozen hair fits with Forster's own research, which indicated that no ancient Eskimo lineage survived in modern-day Greenland populations.
(Explore an atlas of the human journey.)
"It fits in exactly with what we predicted so I'm delighted," he said.
Lead author Gilbert and colleagues suggest that past ancient Eskimo populations succumbed to periods of climate cooling.
"Obviously it's an extremely tough environment up there, and it may be that the environments got so harsh that the populations got smaller and smaller and collapsed," he said.
Forster agreed, adding that the disappearance of Greenland's Paleo-Eskimos coincided with a cooling event that reached its peak 2,800 years ago.
Likewise a later cooling episode known as the little ice age, which lasted from A.D. 1350 to 1850, is credited with wiping out any modern genetic trace of Greenland's first European settlers—the Vikings, Forster noted.
SOURCES AND RELATED WEB SITES