Mammoth As Alaska’s permafrost vials have revealed, North America may have survived thousands of years longer than scientists had previously thought.
The hairy beast may have survived about 5,000 years ago in what is now the Yukon Territory of Canada. This is 5,000 years longer than previously estimated by experts.The conclusion comes from a fragment of the mammoth DNA It was found in a forgotten vial of frozen soil that had been stored in a laboratory freezer for 10 years.
“Organisms constantly release cells throughout their lives,” said Tyler Marchy, a postdoctoral fellow at McMaster University’s Faculty of Anthropology, Ontario. For example, he explained that a person releases about 40,000 skin cells per hour on average. This means that we are constantly releasing some of our DNA to the surroundings.
It also applies to other life forms. Non-human animals, plants, fungi and microbes always leave a fine breadcrumb trail everywhere. However, most of this genetic detritus goes beyond the environment. Immediately after being discarded, most of the DNA bits are consumed by microorganisms, Murchie said. Some of the remaining shed DNA may be bound to and preserved in small amounts of mineral deposits. Although only a small portion of what was initially shed remains centuries later, it can nevertheless provide a window to a disappearing world full of strange creatures.
“In small soil spots, DNA from the complete ecosystem,” Murchie told Live Science.
Murchie analyzed soil samples taken from the permafrost layer in central Yukon. Many of the samples date back to the transition from the Pleistocene to the Holocene (14,000 to 11,000 years ago). During this time, Saber Tooth Eddie Cut, Mammoth, Mastodon — Disappeared from fossil records.
The DNA fragments in Murchie’s samples were small, often less than 50 characters or base pairs. However, on average, he was able to isolate about 2 million DNA fragments per sample. He indirectly observed the evolution of ancient ecosystems during this turbulent era by analyzing DNA from soil samples of known age.
The main advantage of studying ancient DNA is that researchers can observe organisms that tend not to fossilize. “Animals have only one body,” Marchier said, and the odds of it fossilizing are not very high. Besides, you have to find it. However, the same animal constantly released innumerable amounts of DNA into the environment throughout its life.
Soil samples spanning 30,000 to 5,000 years ago revealed that mammoths and horses may remain in this Arctic environment much longer than previously thought. .. According to DNA data, mammoths and horses declined sharply due to the transition from the Pleistocene to the Holocene, but did not disappear all at once due to climate change and overfishing.
Previous studies published in the journal in October Nature, Suggested that some mammoths survived on an isolated island away from human contact until 4,000 years ago. However, this new study was the first to determine that a small population of mammoths coexisted with humans until the Holocene in mainland North America, as it was 5000 years ago.
.. The extinction of Megafauna in this era is largely due to one of two explanations: the ancient human hunter or the catastrophe of the climate, the lead author of evolutionary geneticist and director of the McMaster Ancient DNA Center. Hendrick Poiner said.
But the new research “moves the focus away from these two controversies that have been plagued. [paleontology] For a long time. ”
He said the team’s research provides evidence that the extinction of Megafauna in North America has far more subtle nuances. There is no doubt that animals were under pressure from both human hunters and the rapidly changing climate. The question is, “How much did they hunt and was it really a turning point?” Poiner told Live Science.
Analyzing ancient DNA from the soil can tell us a lot about ancient life. Poinar and Murchie stated that the Arctic permafrost is ideal for these types of ancient DNA studies, as freezing preserves ancient DNA so well. But that may not be possible forever. “We will lose much of our life history data,” says Marchie, as Arctic ice melts as temperatures rise sharply. “It will just fall before anyone gets the chance to study it.”
This study was published in the journal on December 8th. Nature Communications..
Originally published on Live Science.
Mammoths and humans have co-existed in North America for much longer than experts thought.
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