Scientists have successfully mapped the first ever nearly complete genome of two Siberian woolly mammoths, shedding light on their evolutionary history and what led to the mass extinction of this iconic species at the end of the Ice Age.

"With a complete genome and this kind of data, we can now begin to understand what made a mammoth a mammoth - when compared to an elephant - and some of the underlying causes of their extinction which is an exceptionally difficult and complex puzzle to solve," evolutionary geneticist Hendrik Poinar from McMaster University said in a statement.

While scientists have long argued that climate change and human hunting were major factors behind the mammoth's extinction, the new findings suggest multiple factors were at play over their long evolutionary history.

To sequence the entire genome, a team of researchers from McMaster, Harvard Medical School, the Swedish Museum of Natural History, Stockholm University and others used specimens taken from the remains of two male woolly mammoths, which lived about 40,000 years apart.

One mammoth, supposedly 45,000 years old, roamed northeastern Siberia, while the other is believed to be from one of the last surviving mammoth populations - living roughly a mere 4,300 years ago on Russia's Wrangel Island, located in the Arctic Ocean.

"We found that the genome from one of the world's last mammoths displayed low genetic variation and a signature consistent with inbreeding, likely due to the small number of mammoths that managed to survive on Wrangel Island during the last 5,000 years of the species' existence," explained Love Dalén, an associate professor of Bioinformatics and Genetics at the Swedish Museum of Natural History.

Using extremely advanced technology, the team was able to gather bits and pieces of highly fragmented DNA from the ancient specimens, which they then used to sequence the genomes. Careful analysis showed the animal populations had suffered and recovered from a significant setback roughly 250,000 to 300,000 years ago. However, another severe decline occurred in the final days of the Ice Age, triggering their ultimate downfall.

"The dates on these current samples suggest that when Egyptians were building pyramids, there were still mammoths living on these islands," said Poinar. "Having this quality of data can help with our understanding of the evolutionary dynamics of elephants in general and possible efforts at de-extinction."

It could also possibly help scientists bring back the woolly mammoth from extinction, a goal they are currently working towards. A team from Harvard University recently reported how they managed to insert 14 mammoth genes into the live DNA of a modern elephant, which could create hybrid elephants capable of living in colder climates.

It's been 3,000 years since the mammoth was wiped out from the face of the Earth, and now for the first time the genes of these ancient animals are alive again - at least, in the lab.

The results are described in the journal Current Biology.

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