Woolly mammoths died out 5,700 years later than expected


While the de-extinction of the Woolly Mammoths isn’t happening anytime soon, it turns out they’ve been around longer than anyone previously thought.

Woolly mammoths seemed to have become extinct when they disappeared from the fossil record, but there is now evidence that they still stomped on snow thousands of years later. Researcher Tyler Murchie of McMaster University in Canada, who led a study recently published in Nature Communications and another in Communications Biology, has discovered mammoth DNA preserved in permafrost. The creatures were losing cells which fell into a deep frost.

“Most of this lost environmental DNA will be broken down or metabolized by bacteria, but a tiny fraction ends up binding to minerals or forming other molecular complexes that preserve these DNA fragments for the long term, in this case for dozens. millennia, ”Murchie said. FIL SYFY.

You would only have to turn your time machine back about 5,700 years to see a mammoth for yourself. Murchie and his team succeeded in isolating sedaDNA, or ancient sedimentary DNA, from bacteria and everything else of those samples to prove that the mammoths were indeed still alive long after the last one breathed its last. Old DNA is fragile and often fragmented. That’s why the researchers used capture enrichment, which involves RNA baiting chemicals designed to bind to the genomes of the only organisms they were interested in.

More DNA could also be sequenced with capture enrichment. Combining this with better extraction methods allowed the team to reconstruct ecosystems that were once dominated by herds of mammoths. Additional data has surfaced since then, an update that appears in the latest study. There was enough mammoth DNA to reconstruct five mitogenomes, or mitochondrial genomes. The mitochondrial genome is the set of genetic information carried by the cell’s mitochondria, which (among other things) are responsible for many energy processes. These genomes show evidence of hybridization resulting from the crossing between different species of mammoths. A particular species is now considered a hybrid.

“We also used supercomputers to compare these sequenced fragments to all other known reference DNAs,” Murchie said. “This was done to determine which piece is likely to belong to which line of organisms, with varying degrees of specificity depending on which part of the genome a fragment comes from.”

Radiocarbon dating determined the age of the samples, and the youngest containing mammoth DNA was around 5,700 years old. Eurasian mammoth DNA has also been found in permafrost, meaning that Eurasian lineages of the same species found their way to North America in one way or another. The samples were carefully examined and re-examined. Murchie and his team had to make sure that these were representations of pure material that had accumulated over hundreds of years without interruption, and even from different animals, although we never really know if any changes. minors potentially hidden in the samples did not appear.

Using genetic mapping and other techniques, most of the DNA belonging to multiple haplogroups in the samples was disentangled. Haplogroups are identified by closely related alleles, or alternate forms of a gene that result from a mutation and are found in the same area of ​​a chromosome. This means that individuals in a population with this gene share a common ancestor. Murchie believes they could have survived even longer under the right conditions, which may still give critically endangered species a more optimistic outlook.

“I think it helps show that animals can persist through genetic bottlenecks for millennia,” he said. “Maybe if humans hadn’t existed and there had been another Ice Age, these animals could have bounced around as much as they did during many previous glacial-interglacial-glacial transitions. It gives some hope to critically endangered animals today. “

Mammoths only stay in the form of fur and bones. If we can reverse the destruction we caused to the habitats of existing endangered species before they were gone forever, at least they could make a comeback.


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