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    Home > Food News > Food Articles > The oldest DNA extraction record was born! A mammoth from permafrost

    The oldest DNA extraction record was born! A mammoth from permafrost

    • Last Update: 2021-02-23
    • Source: Internet
    • Author: User
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    the oldest record that DNA can be extracted? The latest record is 1.65 million years, extracted from the teeth of mammoths in Siberian permafrost. Previous DNA records were from the Yukon region of Canada, a section of the leg bone of a horse between 560,000 and 780,000 years ago.
    the latest findings were published on February 17th, local time, in nature, an authoritative international academic journal. Scientists extracted DNA from a group of mammoth tooth samples excavated in the 1970s and identified a new mammoth species that once thrived in the Americas.
    "I like this paper. I've been waiting, I've been waiting for eight years. Ludovic Orlando, an ancient DNA expert at the French Centre for Anthropology and Toulouse Genomics, said. He may have been most affected by the discovery, and Orlando and his team set the oldest DNA extraction record in 2013 when they extracted the genome from the horse's leg bone.
    had assumed that ancient DNA could have existed for more than a million years if the right samples had been found. When an organism dies, its chromosomes break into pieces, and over time the chromosome becomes shorter. Eventually, the DNA chain becomes so small that even if it can be extracted, too much genetic information is lost.
    team in Orlando, Canada, found that genetic information from horse bones in the Yukon region of Canada could be explained even by fragments as short as 25 DNA letters. They estimate that, in the absence of permafrost for years, a million-year-old remains, if preserved, should also contain fragments of DNA of this length. Orlando says the only question is, is there such a sample?
    , an evolutionary geneticist at the Swedish Museum of Natural History in Stockholm, has been working on genetic sequencing since he first encountered the remains of a giant mammoth in 2007. The remains of the mammoths were excavated by Russian palaeontologist Andrei Sher. After Darren's identification, there is a real mammoth (Mammuthus primigenius) and two predecessors known as the prairie mammoths (Mammuthus trogontherii).
    the DNA information taken from the sample would reveal the evolution of real mammoths or other mammoths, but he wasn't optimistic about that idea. Because in recent years, many of the more recent mammoth remains found in the permafrost have not been extracted too well. Not everything found in permafrost works, says Darren, and many DNA fragments are ineffective.
    two of the three mammoth molars excavated from Sher had been recovered from sediments over a million years and contained very little DNA. If the samples hadn't been old enough, Darren said, he might have given them up.
    , however, thanks to advances in sequencing technology and bioinsyntics, his team managed to obtain information on 49 million base pairs from the oldest sample, which was named Krestovka because it was located near a village called Krestovka. The other tooth extracted 884 million base pairs, named Adycha. Dna analysis showed that the Krestovka sample was 1.65 million years old, while the Adycha sample had a life span of 1.3 million years. The third sample, a 600,000-year-old mammoth tooth called Chukochya, extracted nearly 3.7 billion base pairs of DNA, more than the length of its 3.1 billion base pairs.
    , the two oldest teeth look like prairie mammoths, a European species. The researchers believe they predepeved the woolly mammoths and the North American Mammuthus columbi. But their genomes paint a more complex picture. The Adycha sample is one of the earlier lineages of the woolly mammoth, but the Krestovka specimen is clearly not.
    's team found that Krastovka belongs to a whole new species. Although Krestovka's samples came from Russia, he suspected that part of his blood had separated from other species and formed the North American mammoth species. The team found that half of the ancestors of the Colombian mammoths in North America were of Krestovka mammoth ancestry and the other half were woolly mammoths. Darren estimates that the two lineages were mixed 420,000 years ago.
    idea that new species can be formed by hybridization rather than splitting from a parent species is becoming increasingly popular among evolutionary biologists. But this is the first evidence of ancient DNA "hybrid species," Orlando said. By
    the threshold of preserving DNA for a million years, paleoDNA researchers may be able to understand the early history of other mammals of all sizes, said Darren. Now, his lab is working on very old samples of permafrost from musk cattle, moose and moose.
    mammoth DNA does not represent the oldest biological molecular information in the fossil record. In 2016, researchers reported a sequence of proteins from the 3.8 million-year-old ostrich eggshells of Tanzania, Africa. In 2019, another team analyzed proteins from 1.77 million-year-old rhino teeth in Georgia, USA. However, protein sequences often lack information about biological inheritance than DNA. But protein molecules are much harder and easier to preserve, so researchers can use very ancient biological information they found in places where there is no permafrost.
    researchers say the chances of finding the remains of ancient human relatives millions of years ago in permafrost are very low. But Darren believes that the right environment, such as caves, could produce old samples. Early Neanderthal remains from Spanish caves date back 430,000 years and represent the oldest DNA of ancient human relatives ever discovered.
    age of ancient DNA, Darren says it's easy to determine: "2.6 million years." That's the limit of permafrost. Until then, the weather was too warm. ”
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