(p. A1) In the permafrost at the northern edge of Greenland, scientists have discovered the oldest known fragments of DNA, offering an extraordinary look at an extraordinary ancient ecosystem.
The genetic material dates back at least two million years — that’s nearly twice as old as the mammoth DNA in Siberia that held the previous record. And the samples, described on Wednesday in the journal Nature, came from more than 135 different species.
Together, they show that a region just 600 miles from the North Pole was once covered by a forest of poplar and birch trees inhabited by mastodons. The forests were also home to caribou and Arctic hares. And the warm coastal waters were filled with horseshoe crabs, a species that today cannot be found any farther north of Maine.
Independent experts hailed the study as a major advance.
“It feels almost magical to be able to infer such a complete picture of an ancient ecosystem from tiny fragments of preserved (p. A8) DNA,” said Beth Shapiro, a paleogeneticist at the University of California, Santa Cruz.
“I think it’s going to blow people’s minds,” said Andrew Christ, a geoscientist at the University of Vermont who studies the ancient Arctic. “It certainly did so for me.”
The discovery came after two decades of scientific gambles and frustrating setbacks.
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. . . the presence of horseshoe crabs in the shallow coastal waters suggests that the ocean and land alike were remarkably warm.
Dr. Willerslev and his colleagues are continuing to study the DNA for clues to how all these species were able to thrive a thousand miles north of the Arctic Circle. The trees, for example, had to survive half the year in darkness. The DNA preserved for two million years may hold their secrets of adaptation.
The scientists are also interested in how the DNA fragments managed to survive so long and defy expectations. Their research indicates that the DNA molecules can cling to minerals of feldspar and clay, which protect them from further damage.
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Dr. Christ said that finding more DNA may help them better understand how human-driven climate change will alter the Arctic. We should not assume, he said, that the region will resemble ecosystems in places farther south. After all, the ecosystem of Kap Kobenhavn two million years ago has no analog today.
“Life will adapt, but in ways we don’t expect,” Dr. Christ said.
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(Note: the online version of the story has the date Dec. 7, 2022, and has the title “Oldest Known DNA Offers Glimpse of a Once-Lush Arctic.”)