Scientists discovered the oldest known DNA and used it to reveal what life was like 2 million years ago in the northern tip of Greenland. Today, it害羞草研究所檚 a barren Arctic desert, but back then it was a lush landscape of trees and vegetation with an array of animals, even the now extinct mastodon.

害羞草研究所淭he study opens the door into a past that has basically been lost,害羞草研究所� said lead author Kurt Kj忙r, a geologist and glacier expert at the University of Copenhagen.

With animal fossils hard to come by, the researchers extracted environmental DNA, also known as eDNA, from soil samples. This is the genetic material that organisms shed into their surroundings 害羞草研究所� for example, through hair, waste, spit or decomposing carcasses.

Studying really old DNA can be a challenge because the genetic material breaks down over time, leaving scientists with only tiny fragments.

But with the latest technology, researchers were able to get genetic information out of the small, damaged bits of DNA, explained senior author Eske Willerslev, a geneticist at the University of Cambridge. In their study, published Wednesday in the journal Nature, they compared the DNA to that of different species, looking for matches.

The samples came from a sediment deposit called the Kap K酶benhavn formation in Peary Land. Today, the area is a polar desert, Kj忙r said.

But millions of years ago, this region was undergoing a period of intense climate change that sent temperatures up, Willerslev said. Sediment likely 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 害羞草研究所� until scientists came along and drilled the samples out, beginning in 2006.

During the region害羞草研究所檚 warm period, when average temperatures were 20 to 34 degrees Fahrenheit (11 to 19 degrees Celsius) higher than today, the area was filled with an unusual array of plant and animal life, the researchers reported. The DNA fragments suggest a mix of Arctic plants, like birch trees and willow shrubs, with ones that usually prefer warmer climates, like firs and cedars.

The DNA also showed traces of animals including geese, hares, reindeer and lemmings. Previously, a dung beetle and some hare remains had been the only signs of animal life at the site, Willerslev said.

One big surprise was finding DNA from the mastodon, an extinct species that looks like a mix between an elephant and a mammoth, Kj忙r said.

Many mastodon fossils have previously been found from temperate forests in North America. That害羞草研究所檚 an ocean away from Greenland, and much farther south, Willerslev said.

害羞草研究所淚 wouldn害羞草研究所檛 have, in a million years, expected to find mastodons in northern Greenland,害羞草研究所� said Love Dalen, a researcher in evolutionary genomics at Stockholm University who was not involved in the study.

Because the sediment built up in the mouth of a fjord, researchers were also able to get clues about marine life from this time period. The DNA suggests horseshoe crabs and green algae lived in the area 害羞草研究所� meaning the nearby waters were likely much warmer back then, Kj忙r said.

By pulling dozens of species out of just a few sediment samples, the study highlights some of eDNA害羞草研究所檚 advantages, said Benjamin Vernot, an ancient DNA researcher at Germany害羞草研究所檚 Max Planck Institute for Evolutionary Anthropology who was not involved in the study.

害羞草研究所淵ou really get a broader picture of the ecosystem at a particular time,害羞草研究所� Vernot said. 害羞草研究所淵ou don害羞草研究所檛 have to go and find this piece of wood to study this plant, and this bone to study this mammoth.害羞草研究所�

Based on the data available, it害羞草研究所檚 hard to say for sure whether these species truly lived side by side, or if the DNA was mixed together from different parts of the landscape, said Laura Epp, an eDNA expert at Germany害羞草研究所檚 University of Konstanz who was not involved in the study.

But Epp said this kind of DNA research is valuable to show 害羞草研究所渉idden diversity害羞草研究所� in ancient landscapes.

Willerslev believes that because these plants and animals survived during a time of dramatic climate change, their DNA could offer a 害羞草研究所済enetic roadmap害羞草研究所� to help us adapt to current warming.

Stockholm University害羞草研究所檚 Dalen expects ancient DNA research to keep pushing deeper into the past. He worked on the study that previously held the 害羞草研究所渙ldest DNA害羞草研究所� record, from a mammoth tooth around a million years old.

害羞草研究所淚 wouldn害羞草研究所檛 be surprised if you can go at least one or perhaps a few million years further back, assuming you can find the right samples,害羞草研究所� Dalen said.

害羞草研究所斺赌斺赌�

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute害羞草研究所檚 Science and Educational Media Group. The AP is solely responsible for all content.

By Maddie Burakoff

THE ASSOCIATED PRESS

Like us on and follow us on .