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Prior to the woolly mammoth, the grassland mammoth, which had been walking through Siberia, had already been genetically adapted to live in a harsh environment. Bet Seiken, courtesy of the Center for High Genetics.

It succeeded in extracting DNA from mammoths 1 million years ago, obtained from permafrost in Siberia. Scientists have analyzed the mammoth’s evolutionary history, revealing that the Colombian mammoth in North America, the symbol of the ice age mammoth, is a hybrid between the woolly mammoth and the mammoth line that has already disappeared. International researchers, including Tom Van der Valk, a researcher at the Swedish Center for High Genetics, said in a paper published in the scientific journal Nature on the 18th that it succeeded in extracting DNA from the molars of three mammoths discovered in northeastern Siberia up to 1.2 million years ago. The oldest record so far was the extraction of DNA from a horse that went extinct 780,000 years ago in the Canadian Arctic in 2013. Extracting DNA, the body of genes from extinct animal fossils, is the key to uncovering the secrets of evolutionary history. DNA analysis can determine which mutations occurred and when and which species diverged from the lineage.

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Throughout the northern hemisphere of African origin

The last mammoth, the woolly mammoth, survived until 2500 BC, when the Egyptian pyramids were built, and there are still many remains of mammoths on the island of Vrangela in the Russian Arctic Ocean. Courtesy of Love Dalen.

However, it is not easy to extract DNA, which is easily decomposed in the environment. This is why old DNA is found in animal carcasses buried in permafrost in Siberia and North America. The researchers used a dental drill to grind the inside of the mammoth molar, which was just a milk pack, while using a mask and face shield to prevent contamination from human DNA. “There was only a small amount of DNA left in the molar tooth, but it was broken up into tiny pieces,” the researchers said in a press release at the Center for Old Genetics. The researchers obtained DNA fragments of about 35 base pairs through a series of chemical treatments from fine bone powder with a size of 0.05 g thus obtained, and they were individually matched with computers to the genome of an extinct old mammoth consisting of about 3.2 billion base pairs. ) Was restored. The result was that we had to rewrite the mammoth genealogy that we have known. “It is known that only one species of grassland mammoth lived in Siberia 1 million years ago,” said lead author Dr. Van der Valk. However, this study revealed that there were two different genetic lines at the time: the Adicha mammoth and the Crestovka mammoth.” Mammoths first appeared in Africa about 5 million years ago and have since spread to many parts of the Northern Hemisphere. The only surviving descendant of this mammoth ancestor is the Asian elephant. During the Flystose (2.6 million to 12,000 years ago), commonly referred to as the Ice Age, mammoths evolved in various ways. At the time of extinction, the woolly mammoths lived close to the North Pole in Eurasia and North America, and the larger Colombian mammoths were distributed farther south of North America, Mexico.

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Mammoth icon is a hybrid

The Siberian mammoths analyzed by the researchers this time revealed that they were 1.2 million, 1.1 million, and 700,000 years ago, much older. The Crestovka mammoth, named after its discovery, is an individual 1.2 million years ago, revealing a new, unknown, extinct mammoth lineage.

Both the Adacha mammoths 1.1 million years ago and the Chukocha mammoths 700,000 years ago were identified as ancestors of the woolly mammoths. The Colombian mammoth of North America appeared as a hybrid of half of the woolly mammoth and the extinct Crestovka mammoth 420,000 years ago. The Colombian mammoth is considered the symbol of the mammoth as it is the largest among mammoths, measuring 4 meters and weighing 10 tons. Humans have also found evidence of hybrids through high genetic analysis. The fact that humans cross with extinct ancient humans, Neanderthals and Denisovans, and contain some of their genes in the genome, was recently revealed through DNA analysis of fossils of ancient human teeth. This study also revealed that woolly mammoths possessed most of the traits for survival in polar environments, such as long hair, body temperature regulation, and fat accumulation, from the days of grassland mammoths, a million years ago. It turns out that adaptation to the extreme environment has gone through a slow and long process.

Mammoth fossils from Siberian permafrost are time machines that can harvest high genes. The upper limit is 2.6 million years ago, the researchers say. Courtesy of Gleb Danilov.

This research has elevated high genetic research to more than 1 million years. Until what point is it possible to analyze the genes of the past to clarify the evolutionary history? The movie’Jurassic Park’ recovers dinosaurs by collecting genes from mosquitoes that sucked the blood of dinosaurs trapped in amber, a fossil mineral that hardened 200 million years ago. However, in reality, high gene extraction is only possible with fossils stored in very special and limited places such as permafrost or caves. “The period when high genes can be extracted may be as far back as 2 million or 2.6 million years,” said a professor at the Andes Goetestrome Center for High Genetics, who participated in the study. I can’t.” Cited Papers: Nature, DOI: 10.1038/s41586-021-03224-9 By Cho Hong-seop, staff reporter [email protected]