It is over a million years old. The world’s oldest DNA ever sequenced was recovered from mammoth teeth buried in permafrost in Siberia, a study published Wednesday (February 17th) revealed. Until now, the record for the oldest genomes deciphered has been held by a horse that is 500,000 to 700,000 years old. “The samples are a thousand times older than Viking remains, and even predate the existence of modern humans and Neanderthals”marveled Love Dalen, from the Center for Paleogenetics in Stockholm, Sweden, who oversaw the study published in the journal Nature (link in English).
The analyzes were carried out on three specimens of mammoths: from fossils discovered in the 1970s in Siberia, in permafrost, and kept at the Russian Academy of Sciences in Moscow, the scientists managed to extract genetic data from from tiny samples of dental powder, “like a pinch of salt to season a dish”, explained at a press conference Love Dalen, professor of genetics.
Thanks to this, they succeeded in sequencing millions of base pairs, the building blocks that make up DNA. Thus, they estimated the age of the animals more accurately than with geological evidence. Verdict: The oldest mammoth, called Krestovka, is 1.65 million years old. The second, Adycha, is 1.34 million years old. And the “youngest” Chukochya, about 870,000 years old.
These analyzes shed new light on the Ice Age, when large mammals reigned. They also teach us about the heritage of the woolly mammoth, whose last survivors disappeared only 4000 years ago from Wrangel Island, off Siberia.
Using the genome of an African elephant, a modern cousin of the mammoth, the researchers also discovered that the oldest, Krestovka, came from a heretofore unknown genetic line, which would have diverged from other species there. was about 2 million years old and then colonized North America. Other analyzes revealed genetic variations associated with life in the Arctic, such as hairiness, thermoregulation or fat deposits, suggesting that mammoths were hairy long before the appearance of their woolly congener.
The thaw of the Siberian permafrost, linked to global warming, brings to light more and more fossils. A real mine that makes scientists eager to study the past of smaller animals as well.
