Paleogenists have deciphered the oldest known DNA to date. It comes from around two million years old sediments in the north of Greenland. As a research group around Eske Willerslev from the University of Copenhagen and the University of Cambridge reports in the specialist magazine »Nature«, she was able to reconstruct the primeval ecosystem from the environmental environmental DNA. The same has not yet been achieved because there are almost no fossil finds from this region. Thanks to improved methods of sequencing, it was now possible to extract and determine such old genetic material, explains the group for Willerslev at a press conference. Previously, the DNA was from three mammoth drives, which survived for more than a million years in the permanent frost floor of Siberia as the oldest surviving genetic material.
Every living being leaves traces of its DNA in its environment – in the form of skin, hair, saliva or feces. The paleogeneticists succeeded in extracting such gene fragments from 41 sediment samples. They had already recovered the material from the permafrost of the so-called Kap København Formation in the north of Greenland in 2006. The sediments that now lie by a fjord had been deposited over a period of 20,000 years. Using geophysical methods, the researchers were able to determine the age of the deposits at 1.9 to 2.1 million years.
Unexpectedly, mastodonts once coexisted with humans in Greenland.
With the help of the gene sections, the working group for Willerslev identified various land and water dwellers: reindeer, rabbits, geese, lemmings, arrow tail crabs as well as birch, thujen, poplars, fungi and bacteria.
Among the gene fragments, the researchers surprisingly also discovered genetic material from mastodontes.
The trunk animals lived on the American continent until the end of the last cold time.
So far, it was unknown that they also met Greenland further north.
It is striking, Willerslev reports during the press conference, that he and his team have not detected any DNA from predators. The paleogeneticist assumes that carnivores must have existed, but their populations were smaller compared to herbivores. "The more biomass [of a species] there is, the more DNA it leaves in the environment," Willerslev says. "And if we had continued sequencing, we would probably have caught carnivores at some point.«
From the gendaten, Willerslev & Co conclude that a Boreal forest grew in northern Greenland two million years ago. The animals and plants come from both arctic and northern climate zones. In addition, the climate was likely to have been warmer in summer and winter around ten degrees Celsius than today. Eske Willerslev emphasizes that comparable ecosystems no longer exist.
DNA can endure in the right soil, even in the cold and dry.
According to the researchers, the fact that the genome fragments have survived for so long has two reasons: On the one hand, the material was in frozen soil - under icy and dry conditions, genetic material is preserved for significantly longer.
On the other hand, the proximity to the sea and the components of the soil could have promoted conservation.
The gene snippets of certain minerals remain better, especially on clay minerals.
This knowledge could give the paleogenicists further sensational finds. "It is possible that Ton Alte DNA [also] preserved in warm, moist environments, to sites in Africa," says Willerslev, according to a press release from the University of Cambridge. "If we can start examining old DNA in toncorns from Africa, we could possibly collect groundbreaking data about the origin of many different types - maybe even new knowledge about the first people and their ancestors." However to break north. In the summer of 2023, the research group in Nordkanada would like to recover sediments and search for old environmental DNA.
