MAMMOTH REVIVAL
Dinosaur fossils are too old to yield DNA which could bring them back à la Jurassic Park. Frozen mammoths, however, could be ripe for a revival.
Dinosaur remains are too old to yield useful DNA, but it may be possible to revive more recently extinct animals. Woolly mammoths well-preserved in ice are prime candidates for an early return.
The last known mammoth died some 4000 years ago on a small Russian island in North Siberia. But perhaps we have not seen the last of this giant species. In 2019, scientists from the Japanese Kindai University in Osaka extracted bone marrow and muscle tissue from a 28,000-year-old mammoth named Yuka which had been excavated near the village of Yukagir in north-eastern Siberia. The scientists identified cell nucleus-like structures and inserted the least damaged of these into egg cells from mice. The cells subsequently showed signs of activity that normally precedes cell division, although they did not eventually reproduce. Nevertheless the scientists declared their experiment to be a “major step towards reviving mammoths”.
George Church from Harvard University in the US hopes to take another key step in the revival of the woolly mammoth. In 2015, Church and his team of scientists managed to introduce DNA from a mammoth into an elephant cell by means of the CRISPR gene editing tool.
“Our purpose is to create a hybrid between an elephant and a mammoth embryo. It will be a kind of elephant with mammoth features,” Church said about the experiment. In the years since then he has extracted new DNA samples from well-preserved mammoths, and he expects a mammoth revival to take place before 2030.
The DNA material for reviving extinct mammoths comes mainly from the Siberian permafrost, where millions of mammoth fossils are buried in a thick layer of ice that has halted or significantly slowed biological processes which normally follow death. Hence mammoth fossils recovered from the ice are often in very good shape.
The first mammoths originated as a subspecies of the African elephant some four million years ago. A million years later, the mammoth species M. rumanus was the first to leave Africa for Europe, and then over time extended its reach to Asia and North America, where new mammoth species evolved that were better adapted to the different temperature ranges.
The last and most famous mammoth species was the woolly mammoth that emerged in Central Asia and Central Europe some one million years ago. The woolly mammoth weighed 5-6 tonnes and was 3-4 metres tall, roughly the same as a modern African male elephant. Unlike its African peer, however, the mammoth had a thick fat layer and long thick fur that allowed it to keep warm even in freezing temperatures.
By the end of the most recent ice age some 10-12,000 years ago, the majority of the mammoths had disappeared. Research indicates that the woolly mammoths succumbed to a combination of intensified hunting activities and shrinking habitat due to climate change that made the ice recede and nutritious herbs disappear. We do not
know exactly to what extent humans were hunting these huge animals, but we do know that the mammoth was much-coveted by Stone Age people. This was confirmed in 2019, when archaeologists discovered 824 mammoth bones and a possibly man-made mammoth trap in Mexico. Other discoveries such as spear marks on the bones of mammoth fossils make scientists suspect that humans may have contributed significantly to sealing the mammoths’ fate.
On Wrangel Island – an Arctic Russian island in the East Siberian Sea – a small group of woolly mammoths managed to survive up until 2000 BC. The island formed part of the major Beringia landmass that linked Siberia and Alaska – i.e. Asia and North America. When huge quantities of inland ice melted towards the end of the ice age, Beringia was flooded, and Wrangel Island was isolated – along with a few hundred mammoths.
According to American scientists from the University of North Carolina, these last mammoths on Earth died due to a series of harmful gene mutations, probably caused by inbreeding. The mutations meant that the mammoth ended up with thinner fur, digestion problems and a defective sense of smell, which made it more difficult to detect pheromones and identify a mate.
Yet now, thousands of years later, today’s scientists are throwing a life-line to these extinct animals using the tools of gene technology and DNA research.
But one nagging question is whether it is wise to ‘play God’ and revive the old giants. Several biologists fear that a reintroduction of the mammoth could provide opportunities for new diseases, or simply unbalance ecosystems and drive other species over the edge. As the professor in Steven Spielberg’s Jurassic Park says to the scientists behind the park’s disastrous revival of dinosaurs: “You were so obsessed with finding out if you could do it that you never stopped to consider whether you should.”
KEI MIYAMOTO
CHIEF RESEARCHER WHO INSERTED MAMMOTH DNA INTO MOUSE EGGS A major step towards bringing the mammoth back from the dead.