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It's true: Greenland was green

July 07, 2007|From the Associated Press

Ice-covered Greenland really was green a half-million or so years ago, covered with forests in a climate much like that of Sweden and eastern Canada today.

An international team of researchers recovered ancient DNA from the bottom of an ice core that indicates the presence of pine, yew and alder trees as well as insects.

The researchers, led by Eske Willerslev of the University of Copenhagen, Denmark, say this is the first proof that there was forest in southern Greenland.

Included were genetic traces of butterflies, moths, flies and beetles, they report in Friday's edition of the journal Science.

The material was recovered from cores drilled through ice 1.2 miles thick at a site called Dye 3 in south central Greenland. Ice cores from another site farther north did not yield any DNA.

Greenland was discovered by Vikings sailing from Iceland about 1,000 years ago. Though it had an ice cap then, the climate was relatively mild and the Vikings were able to establish colonies in coastal areas. Those colonies vanished as the area cooled.

But the new research shows it hasn't always been so cold there.

"These findings allow us to make a more accurate environmental reconstruction of the time period from which these samples were taken, and what we've learned is that this part of the world was significantly warmer than most people thought," Martin Sharp, a glaciologist at the University of Alberta, Canada, and a coauthor of the paper, said in a statement.

The base of the ice Willerslev's team studied is mixed with mud.

The DNA, dated between 450,000 and 800,000 years ago, may be the oldest yet recovered, according to the team. DNA found previously in the Siberian permafrost has been dated to 300,000 to 400,000 years ago.

Because of uncertainties in interpreting the age estimates, they could not rule out the possibility that the new DNA dates to 130,000 to 116,000 years ago.

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