Oldest DNA reveals life in Greenland 2 million years ago
NEW YORK — Scientists discovered the oldest known DNA and used it to reveal what life was like 2 million years ago in Greenland. Today, it’s a barren Arctic desert, but then, it was a lush landscape of trees and vegetation with an array of animals.
“The study opens the door into a past that has basically been lost,” said Kurt Kjær, a geologist and glacier expert at the University of Copenhagen.
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The researchers extracted environmental DNA, or eDNA, from soil samples. This is the genetic material that organisms shed into their surroundings.
Studying old DNA can be a challenge because material breaks down over time, leaving scientists with fragments. But with new technology, researchers were able to get genetic information out of small, damaged bits of DNA, explained author Eske Willerslev, a geneticist at the University of Cambridge. In their study, they compared the DNA to that of different species, looking for matches.
The samples came from a sediment deposit called the Kap København formation in Peary Land. Today, the area is a polar desert.
But millions of years ago, this region was undergoing a period of intense climate change that sent temperatures up. Sediment built up for tens of thousands of years at the site before the climate cooled and cemented the finds into permafrost.
The cold environment would help preserve the delicate bits of DNA — until scientists came along and drilled the samples out, beginning in 2006.
One big surprise was finding DNA from the mastodon, an extinct species that looks like a mix between an elephant and a mammoth, Kjær said. Many mastodon fossils have previously been found from temperate forests in North America. That’s an ocean away from Greenland, and much farther south, Willerslev said.
