By sequencing environmental DNA from Greenland, scientists have been able to reconstruct the region’s ecosystem 2 million years ago. A feat.
DNA contains valuable information — sometimes about an entire environment and the species, it contains. And the advantage, for paleontologists, is that it can be preserved for millions of years. By diving into these genetic traces, we then go back in time. This is what scientists managed to do for a study published on December 7, 2022, in Nature.
At a site in Greenland, researchers have succeeded in taking DNA from sediments frozen in permafrost. So old, in fact, that these date back 2 million years. The research team then sequenced these findings to extract information. And then a whole world emerged from these data. A world all the more foreign that at this precise time in Greenland the region was warmer than today.
“A new chapter covering an additional million years of history has finally been opened and, for the first time, we can directly examine the DNA of an ecosystem that has passed so far back in time “, enthuses the head of the Eske Willerslev team. “DNA can degrade quickly, but we have shown that, given the right circumstances, we can now go back further in time than anyone would have dared to imagine.”
Mastodons prowled Greenland
The genetic reconstruction of this environment shows a very vast biodiversity — more than today. Reindeer, hares, lemmings, animals similar to deer, and black geese lived on the lands of Greenland at that time, where there were also, on the flora side, birches, spruces, and poplars. Several plants discovered in the DNA are unable to grow on permafrost, a valuable clue to represent this ecosystem.
The famous mastodons were also present – which is a real discovery since it was previously thought that the range of these animals (of the same order as elephants and mammoths, but not of the family) did not extend to Greenland.
They are not mammoths or elephants, but mastodondes! They belong to the same order, but not to the same family. Source: Beth Zaikenjpg
Added to the cartography of this lost world, are many unicellular microorganisms (bacteria, fungi). The next stage of this research is also the relationship between all these living beings: how did the biological interaction between animals, plants, and microorganisms work?
This work also has a very current interest: it is paleoclimatology. Studying past climates and ecosystems provides insight into current human-caused climate change. Including how species may or may not adapt.