L’DNA (Deoxyribonucleic acid) encodes all the information concerning living beings and provides a lot of information on the evolution of species. But the elements that constitute it are relatively fragile and degrade quickly in the open air, even if they can already constitute a promising and durable storage medium for computing.
Under certain circumstances, DNA can be stored longer when it is locked away and protected from outside influences. However, scientists have until now believed that 1 million years corresponded to the “survival” limit of the substance in nature. Much too short to hope to one day recover dinosaur DNA, but enough to extract it from Siberian mammoth teeth, which was the oldest DNA collected until then.
When the mastodons frolicked in Greenland…
A discovery made in Greenland and published in the journal Nature nevertheless reveals that DNA can resist much longer than estimated. Sediments taken from the soil and ancient cliffs of the Arctic have revealed 2 million year old genetic tracesconstituting a new record and providing valuable information on the animal life and flora present in this area in these remote times.
The study reveals in particular the presence of behemothsthese large cousins of the elephant still present in North America 10,000 years ago and since extinct, suggesting that Greenland was covered in vast forests two million years ago, earning its translation green”.
This is a surprise as no mastodon fossils have been found in Greenland and a sign that the animals may have managed to colonize the island from the US mainland.
Permafrost, a natural freezer
It’s the permafrostthis continuously frozen ground, which makes it possible to make such discoveries of very ancient DNA by imprisoning by freezing sediments and DNA fragments, but its very age (just over 2 million years) suggests that it it will hardly be possible to find even older genetic traces…unless our knowledge continues to evolve by then.
The discovery also provides information on the local climate and the variations that the geographical area has experienced, with the regular adaptation of local and migrating species, also showing reindeer, hares and a wide variety of plants.
This portion of Greenland was therefore rather a temperate zone at the time with temperatures of 11 to 17 degrees and always the long periods of presence or absence of the sun.
Permafrost is under close scrutiny by scientists. Its rapid melting caused by global warming releases large quantities of greenhouse gases previously trapped in the frozen ground and which can accelerate the mechanisms of climate change.
There is also concern about the possible reawakening of ancient pathogens. The reactivation of a 48,500 year old “zombie virus” confirms this possibility, even if nothing says that it would survive for long under current climatic conditions.