Ancient DNA Reveals Greenland Had Rich Forest Life within Past Million Years

A reconstruction of southern central Greenland based on findings from the Dye 3 basal ice.
[Image © Science]

Scientists analyzing ancient DNA from ice cores extracted from deep beneath Greenland's ice sheets have found that parts of the island were once covered by rich forests.

Publishing in the 6 July issue of Science, Eske Willerslev and an international team investigated what lies beneath the ice sheets of Greenland by extracting and amplifying ancient DNA from the silty sections of deep ice cores from just above the bedrock.

Studying sediment beneath two kilometers of ice, the researchers discovered evidence of an ancient, diverse boreal forest wild with pine, spruce, alder, and yew. In addition, DNA sequences suggest that butterflies, moths, and ancestors to modern beetles, flies, and spiders once inhabited the island that is now 80% covered with ice.

Although the dating of the samples remains uncertain, the DNA has been preserved under ice for at least 130,000 years, and possibly up to 1 million years.

The researchers write that obtaining natural history of icy places like Greenland, a territory of Denmark, is difficult because much of the fossil evidence has been hidden or scoured away during glacial expansion.

"The environmental histories of high-altitude regions such as Greenland and Antarctica are poorly understood because much of the fossil evidence is hidden below kilometer-thick ice sheets," wrote Willerslev, lead author and a biologist at the University of Copenhagen in Denmark.

Evelyn Brown and Benjamin Somers

6 July 2007