Scientists have discovered a 2-million-year old DNA from Ice Age sediments in Greenland, a discovery that opens a new chapter for paleogenetics, scientists announced on Wednesday, AFP reports.
“DNA can survive for 2-million-years, which is twice as old as DNA found previously,” says Mikkel Winther Pedersen, one of the lead authors of the study published in the scientific journal Nature
According to the report by AFP, the world’s oldest DNA identified in sediments, the different DNA fragments come “from the northernmost part of Greenland, called Cape Copenhagen, and (are) from an environment that we do not see anywhere on Earth today”, Mikkel Winther Pedersen.
They were so well preserved because frozen and found in areas that have been little exploited, continues the lecturer at the University of Copenhagen.
“The rivers (carried) minerals and organic matter into the marine environment, where these land sediments were deposited. And then, at one point, about 2 million years ago, this land mass under the water was uplifted and became part of North Greenland,” he says.
Cape Copenhagen is today 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.
2-million-year old DNA: 16 years of research
The work of the researchers, which began in 2006, has made it possible to paint a portrait of the region 2 million years ago.
“We had this forest environment with mastodons, reindeer and hares and with a large number of different plant species. We found 102 different plant taxa”, notes Mikkel Winther Pedersen.
According to him, the presence of mastodon is particularly notable because it had never before been noted so far north.
Researchers are therefore reflecting on the adaptability of species because two million years ago Greenland – “green earth” in Danish – experienced temperatures 11 to 17 degrees higher than those of today but in these latitudes, the sun does not set in the summer months nor does it rise in the winter.
“We do not see this association of species anywhere else on Earth today,” said the specialist in paleo-ecology. This “makes you think about the plasticity of species: how species are actually able to adapt to a climate, to different types of climates, might be different from what we previously thought.”
State-of-the-art technology
It was thanks to innovative technology that the researchers discovered 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 the quartz and 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 leads the geobiology group at the University of Copenhagen and participated in the study.
For Mikkel Winther Pedersen, with this discovery, “we are breaking the barrier of what we thought we could achieve in terms of genetic studies”.
“It was long thought that a million years was the limit of DNA survival, but today we are double that. And obviously, that drives us to look for sites,” he adds.
“There are several different sites around the world that have geological deposits that go back that far. And even further back in time,” says the researcher.