February 3, 2023

Dawson County Journal

Dawson County, Nebraska

Oldest known DNA paints stunning picture of life 2 million years ago

A group of international scientists have recovered the oldest known DNA and used it to reveal what life was like 2 million years ago in northern Greenland. 

In research published Wednesday in the journal Nature, the group said that biological communities inhabiting the Arctic during the late Pliocene and early Pleistocene epochs remain poorly known because fossils are rare. 

With animal fossils hard to find, the researchers extracted environmental DNA from soil samples, including the genetic material that organisms shed into their surroundings.

Researchers were able to get genetic information out of the small, damaged bits of DNA using the latest technology – comparing the DNA to that of different species.

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The samples came from a sediment deposit called the Kap København formation in Peary Land. 

Senior author Eske Willerslev, a geneticist at the University of Cambridge, said that millions of years ago the region was undergoing a period of intense climate change that sent temperatures rising and sediment likely built up for tens of thousands of years before the climate cooled and cemented the finds into permafrost – helping to preserve the DNA until the extraction process began in 2006.

While the area is a barren Arctic desert today, back then the group found the landscape to have been lush, with Arctic plants and animals including the extinct mastodon.

“Of note, the detection of both Rangifer (reindeer and caribou) and Mammut (mastodon) forces a revision of earlier palaeoenvironmental reconstructions based on the site’s relatively impoverished faunal record, entailing both higher productivity and habitat diversity for much of the deposition period,” the authors wrote.

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During the warm period, average temperatures were 20 to 34 degrees higher than today. 

The DNA also showed traces of geese, hares, reindeer and lemmings, and the sediment built up in the mouth of a fjord suggested that horseshoe crabs and green algae lived in the area. 

Although Laura Epp, an environmental DNA expert at Germany’s University of Konstanz who was not involved in the work noted that, based on the data, it’s hard to say for sure whether these species truly lived side by side.

Lead author Kurt Kjær, a geologist and glacier expert at the University of Copenhagen, said that means waters were likely much warmer back then.

Willerslev believes that because these plants and animals survived during a time of dramatic climate change, the DNA could offer a “genetic roadmap” to help the world adapt to current warming.

He told Reuters that he would not be surprised to find DNA from at least 4 million years ago. 

“Similar detailed flora and vertebrate DNA records may survive at other localities,” the scientists said. “If recovered, these would advance our understanding of the variability of climate and biotic interactions during the warmer Early Pleistocene epochs across the High Arctic.”

Reuters and The Associated Press contributed to this report.


Source: Science