A team of scientists has 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 Greenland is a barren arctic wasteland, but back then it was a lush region filled with trees, plants and myriad animals, including the now-extinct mastodon, according to the Associated Press.
Discover the secrets of the deep past
Lead researcher Kurt Kjaer, a geologist and glacier expert at the University of Copenhagen, said the study opens a window into secrets of the distant past.
With animal fossils so hard to find, researchers have extracted environmental DNA, also known as eDNA, from soil samples. eDNA is the genetic material that organisms release into their surroundings, such as hair, excrement, spit or decaying corpses.
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Latest technology
Studying ancient DNA can be a challenge because the genetic material degrades over time, leaving only tiny fragments for scientists. But researcher Eske Willerslev, a geneticist at the University of Cambridge, explained that using cutting-edge technology, the researchers were able to obtain genetic information from small fragments of damaged DNA, as DNA from different species was compared looking for matches, according to the journal Nature.
severe climate change
The scientists obtained the samples from a deposit called the Cap Copenhaven Formation in Berryland. Kiar said the region today is a polar desert, while Willerslev explained that this region was going through a period of abrupt climate change millions of years ago which led to rising temperatures. The sediments may have accumulated for tens of thousands of years at the site before the climate cooled and the finds solidified in the permafrost.
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Trees and plants
The researchers report that during the region’s warm period, when average temperatures were 11 to 19 degrees Celsius higher than today, the region was filled with a surprising variety of plant and animal life. The DNA fragments indicate a blend of arctic plants, such as birch and willow, with those that prefer warmer climates, such as fir and cedar.
Animals and marine life
The DNA showed traces of animals, including geese, hares and reindeer, Willerslev said. Previously, dung beetles and some rabbit remains were the only signs of animal life at the site.
One of the big surprises, Kiar added, was finding DNA from a mastodon, an extinct species that looked like a cross between an elephant and a mammoth.
Many mastodon fossils have previously been found in temperate forests of North America. It’s an ocean further south than Greenland, Willerslev said.
As sediments accumulated at the mouth of the fjord, the researchers were also able to obtain clues about marine life from this time period. DNA indicates horseshoe crabs and green algae lived in the area, which Kyarr says means the nearby waters may have been much warmer at the time.
road map
Researcher Willerslev believes these plants and animals may have survived a period of dramatic climate change, so their DNA could provide a ‘genetic roadmap’ to help us adapt to current warming.
