Astonishing achievement: Mammoth researchers have deciphered the sequences of the world’s oldest known DNA samples

According to the researchers, the DNA was found in teeth belonging to three mammoths, one of which lived about 800,000 years ago. years, and the other two more than a million years ago. Studying this genetic material provides important data on large glacial mammals, including information on mammoth ancestors.

These genomes are significantly older than the oldest known DNA samples studied, which belonged to a horse that lived between 780 and 560 thousand years ago. years.

“THIS DNA is incredibly old. The specimens are a thousand times older than the remains of the Vikings and even predate [šiuolaikinius] people and Neanderthals, ”said Love Dalen, a professor of evolutionary genetics at the Center for Paleogenetics in Stockholm, one of the authors of a paper in the journal Nature.

Mammoth remains were found in Siberia in the 1980s and stored in the funds of the Russian Academy of Sciences in Moscow.

The researchers initially determined the age of the residues by geological methods, comparing them with the distribution of fossils in other species, especially small rodents, which are characteristic only of certain periods, in the same sediment layers.

These studies suggested that the two animals were ancient steppe mammoths (Mammuthus trogontherii) that lived more than a million years ago.

The last remains of the mammoth belonged to the woolly mammoth (Mammuthus primigenius), but this individual is one of the earliest known representatives of its species.

DNA puzzle

The researchers also isolated genetic material by taking powdered material from inside teeth, “like a pinch of salt sprinkled on the lunch plate,” Dalen told a news conference.

Although the DNA strands were divided into very small fragments, the researchers were able to scan tens of millions of nucleotide pairs and pair them together to determine the approximate age of the genetic information.

The researchers used this method to discover that the oldest mammoth, named “Krestovka,” is actually older than it looks – 1.65 million. years. The second, Adyčia, lived about 1.34 million years ago. years, and the last – “Čiukočia” – wandered 870 thousand years ago. years.

Dalen said the discrepancy between the dating results of older mammoth residues could be due to an error in DNA sequencing. It is likely that this mammoth lived about 1.2 million years ago. years, as geological data show.

However, he did not rule out the possibility that this individual was in fact earlier, but at some point his thawed remains could have been pushed out of the permafrost and transferred to later sediments.

The DNA fragments were like a puzzle made up of millions of tiny details: “much, much smaller than what you get from modern high-quality DNA,” said Tom van der Valkas, lead author of the study at the Science Laboratory of Life at Uppsala University.

Using the genome of the African elephant, which is a modern close relative of mammoths, the researchers developed an algorithm to help reproduce fragments of fragments of mammoth genetic material.

The study shows that the oldest mammoth, Krestovka, belongs to a hitherto unknown genetic line. According to scientists, it diverged from the evolutionary line of other mammoths about 2 million years ago. years and is related to the ancestors of mammoths widespread in North America.

At that time, the genome of the Adyčia steppe mammoth is closer to Čiukočiai and other woolly mammoths that lived later.

Researchers have discovered DNA variants in older animals that are linked to life in arctic conditions, such as those that determine body hair and thermoregulatory mechanisms, fat accumulation, and resistance to frost. They hypothesize that mammoths were covered in dense hairs much longer than woolly mammoths evolved.

Giants of the Ice Age

During the ice age, dry and cold periods in Siberia alternated with warmer and wetter periods.

But now, due to climate change, the permafrost layer is thawing, revealing more and more ancient animal remains that have survived in it, Dalen said. However, the scientist regretted that due to more rains these remains are washed away.

According to L. Dalen, new technologies may open up opportunities to study much older ones found in permafrost, some 2.6 million years ago. DNA sequences of animal residues.

Scientists are looking to study the genomes of modern moose, sheep, wolves and lemurs to learn more about the evolution of species.

“Genome science goes back to ancient times because of these glacial giants,” said Alfred Roca, a professor in the Department of Animal Sciences at the University of Illinois, who published a comment on the new study in the journal Nature.

“The day of the small mammals that surrounded them may also come soon,” he added.