DNA from 2 Million Years Ago Reveals a Lost Arctic World | Science

Two-million-year-old DNA from the north Greenland revealed that the region was once home to mastodons, lemmings and geese, offering unprecedented insight into how climate change can shape ecosystems.

Breakthrough in ancient DNA analysis pushes DNA record back a million years to a time when the Arctic the area was 11-19C warmer than today. Analysis reveals that the northern peninsula of Greenland, now a polar desert, once featured boreal poplar and birch forests teeming with wildlife. The work offers clues as to how species might adapt, or be genetically modified, to survive the threat of rapid global warming.

Professor Eske Willerslev from the University of Cambridge and the University of Copenhagen, said: “A new chapter spanning another 1 million years of history has finally been opened and for the first time we can look directly at the DNA of a past ecosystem that goes back a long way.”

The fragments are 1 million years older than the previous DNA record taken from a Siberian mammoth bone. “DNA can degrade quickly, but we’ve shown that under the right circumstances, we can now go back further in time than anyone dared to imagine,” Willerslev said.

In the future, similar techniques could be used to uncover new information about early humans and their ancestors, he added.

Willerslev and his colleagues worked for 16 years on the project, culminating in the sequencing and DNA identification of 41 samples found hidden in clay and quartz. The ancient DNA samples were found buried deep in the Kap København Formation, a sediment deposit nearly 100 meters thick that has accumulated over 20,000 years. The sediments, nestled in the mouth of an Arctic Ocean fjord in far northern Greenland, were eventually preserved in ice or permafrost and remained undisturbed for 2 million years.

DNA extraction and analysis was a painstaking process that involved piecing together tiny fragments of genetic material that first had to be detached from the clay and quartz sediments. It was not until the advent of a new generation of DNA sequencing techniques that allowed scientists to identify and piece together extremely small and damaged DNA fragments, referencing vast DNA libraries. collected from living animals, plants and microorganisms.

A picture emerged of forests populated by reindeer, hares, lemmings and mastodons, elephant-like Ice Age mammals previously found only in North and Central America.

The samples revealed no carnivores – likely because there were fewer of them – but scientists have speculated that there may have been ancient bears, wolves or saber-toothed tigers. “We don’t know what was there, but probably something that ate mastodons and reindeer,” Willerslev said.

The authors say it’s encouraging that these species were able to thrive so far north in an area that would still have been shrouded in darkness for much of the winter, despite warmer temperatures.

“The data suggests that more species can evolve and adapt to wildly variable temperatures than previously thought,” said Dr Mikkel Pedersen, from the Lundbeck Foundation Center for Geogenetics at the University of Copenhagen. and co-first author.

However, the speed of current global warming means that many species will not have enough time to adapt, which means the climate emergency remains a huge threat to biodiversity. Willerslev and his colleagues said studying ancient ecosystems could provide clues to how certain species were genetically adapted to a warmer climate.

“It is possible that genetic engineering could mimic the strategy developed by plants and trees 2 million years ago to survive in a climate characterized by rising temperatures and prevent the extinction of certain species, plants and trees. “said Professor Kurt Kjærr, from the University of Copenhagen and a co-author. “That’s one of the reasons why this scientific breakthrough is so important because it could reveal how to try to counter the devastating impact of global warming.”

The results are published in the journal Nature.

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