World's oldest DNA discovered in Greenland is 2 million years old

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Discovered in Greenland, the oldest DNA in the world is 2 million years old

Cape Copenhagen, Greenland, two million years ago, when the temperature was significantly higher than today in the far north of Greenland.

De l& Two-million-year-old DNA, the oldest ever extracted, has been unearthed from ice-age sediments in Greenland, a discovery opening a new chapter for paleogenetics, announced Wednesday of scientists.

DNA can survive for 2 million years, which is twice as old as previously found DNA, Mikkel Winther Pedersen, one of the world's leading scientists, told AFP. authors of the study published in the scientific journal Nature (in English).

Identified in sediments, the various fragments of; DNA come from the northernmost part of Greenland, called Cape Copenhagen, and [are] from an environment that we don't see anywhere on Earth today, he says.

They were so well preserved, because they were frozen and found in surfaces that had been little exploited, continues the lecturer at the University of Copenhagen.

“The rivers [carried] minerals and organic matter into the marine environment, where these terrestrial sediments were deposited. And then, at some point, about 2 million years ago, this underwater land mass was lifted up and became part of North Greenland.

— Mikkel Winther Pedersen, University of Copenhagen

Cape Copenhagen today is an arctic desert. Different types of deposits, including excellently preserved fossils of plants and insects, had already been discovered there. The researchers had not sought to establish the DNA of the elements found and very little information existed on the possible presence of animals.

The researchers' work, which began in 2006, has painted a portrait of the region 2 million years ago.

“We had this forest environment with behemoths, reindeer and hares and with a lot of different plant species. We found 102 different plant taxa. »

— Mikkel Winther Pedersen, University of Copenhagen.

Researchers therefore reflect on the adaptability of species, because 2 million years ago Greenland – “green earth” in Danish – experienced temperatures 11 to 19 degrees Celsius higher than those of ;today, but at these latitudes the sun does not set in the summer months or rise during the winter.

We do not see this association of species nowhere else on Earth today, underlined the specialist in paleoecology. This makes you think about species plasticity: how species are actually able to adapt to a climate, to different types of climates, might be different than we previously thought.

It was thanks to innovative technology that researchers found that the 41 fragments studied are a million years older than the previous record of DNA taken from a Siberian mammoth bone. .

It was necessary to determine if DNA was hidden in the clay and quartz, then that it was possible to detach it from the sediment to examine it.

The method used provides a fundamental understanding of why minerals or sediments can preserve DNA…it's a Pandora's box we're about to open, says Karina Sand, who heads the geobiology group at the University of Copenhagen and was involved in the study.

For Mr. Winther Pedersen, with this discovery, we break the barrier of what we thought we could achieve in terms of genetic studies.

“We have a long thought that a million years was the limit of DNA survival, but today we are double that. And obviously, that pushes us to look for sites.

— Mikkel Winther Pedersen, University of Copenhagen

There are several different sites around the world that have geological deposits that date back this far. And even further back in time, welcomes the researcher.

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