Scientists uncover oldest known DNA on Earth

Friday, July 6, 2007

Animation of the structure of a section of DNA.
Image: Richard Wheeler.

Ice samples retrieved from 1.2 miles (2 km) beneath the surface of Greenland have uncovered the oldest known samples of DNA from insects. The samples, estimated to be 450,000-900,000 years old, have also shown that no more than one million years ago, Greenland was once home to forests and animal life.

"We have shown for the first time that southern Greenland, which is hidden under 2 km of ice, was once very different to the Greenland we see today. Back then, it was inhabited by a diverse array of conifer trees and insects," said Professor and leader of the team who made the discovery, at the University of Copenhagen in Denmark, Eske Willerslev.

"This genetic material presents a biological environment which is completely different to today. We have found grain, pine, yew and alder. These correspond to the landscapes we find in eastern Canada and in Swedish forests today," added Willerslev.

Willerslev also says that because of the presence of the yews, the temperatures in that area of Greenland could not have been "lower than -17 degrees Celsius" and that with the variety of other trees, the summer temperatures were no lower than "10 degrees Celsius."

These findings could change the history of Greenland. The current theory is that Greenland was free from its ice no more than 125,000 years ago. The results of the findings now suggest that Greenland may have been covered with ice for at least 450,000 years.