Harvard geneticist and co-founder George Church said: “This is the most important thing in the project so far. “There are many steps ahead.”
For proponents, bringing back extinct animals is an opportunity to redress humanity's role in the ongoing extinction crisis. Advances in their field, they say, could benefit animals we still have, including the endangered elephant.
Nevertheless, the technological challenges to birth a living, breathing giant in the world remain enormous. The project raises crucial ethical questions: Who decides what should be returned? Where will the reincarnation race go? Could the money be better spent elsewhere? How hard will “extinction” be on animals, as revival efforts are known?
“What worries me about animal welfare is the lack of knowledge,” says Heather Browning, a philosopher and former zookeeper at the University of Southampton in England.
Can we really bring back the mammoth?
During the last ice age, the woolly mammoth ruled the world, spreading across Eurasia and North America and south to the modern Midwest.
As the species went extinct 4,000 years ago, some carcasses were frozen in the icy tundra, preserving not only their bones but also their flesh and fur, giving paleontologists the opportunity to collect DNA fragments. Some of the mammoth meat was so well preserved that at least one adventurer ate it.
By 2015, scientists had sequenced its genetic map enough to provide a possible manual for remaking a mammoth. But to test what exactly each of these genes do—give the beast their curved tusks, fat and thick fur—Church wanted elephant stem cells, in which he could create mammoth DNA and grow tissue samples.
Scientists have was produced Such stem cells are available in the laboratory for other animals, including humans, mice, pigs and rhinos. But for years, getting the right elephant stem cells to test those cold-weather traits proved elusive because the elephant cells' ability to evade cancer made them difficult to reprogram.
By suppressing anti-cancer genes and bathing the cells in the right chemical cocktail, Kolochin produced the stem cells they needed. Colossal released a preprint on Wednesday that has yet to be peer-reviewed. The company said it is working to place the study in a peer-reviewed scientific journal.
“It's not straightforward,” said Eriona Hysolli, president of the Institute of Biological Sciences. “It wasn't immediately obvious. There was a lot of innovation along the way.”
Gene Loring, a Scripps Research researcher in California who helped develop powerful stem cells for the northern white rhino, praised the elephant researchers' persistence. “It's an incredibly steep hill ahead of them,” he added. “The challenges get bigger and bigger with the size of the animals.”
Ultimately, the company wants to genetically edit an embryo A stem cell with mammoth genes and attach it to an elephant egg. From there, if all goes as planned — and if it's still big — they'll implant the fetus into an elephant surrogate and wait for it to be born.
Even if we can, should we?
Matthew Cobb, a zoologist at the University of Manchester in England, said all those “ifs” may be insurmountable. There is no guarantee that modified chromosomes can be introduced into an elephant cell or that it will take hold in the elephant's womb.
Perhaps more deeply, there is the question of how a mammoth, once born, learns to behave like a mammoth. “Most spoken mammals and birds have lost complex social and cultural interactions,” Cobb said. “It's simply not their genes.”
For example, modern elephants are highly social beings, passing knowledge of irrigation and other survival skills from one generation to the next. So may their ancient relatives. “They don't have adults to raise them and teach them,” Browning said. “They have no way of learning how to be mammoths.”
Also, any live surrogate elephant that becomes pregnant and gives birth to a new mammoth will face some hardships. “How many dead elephants do we need to get one piece of wool?” said Tory Herridge, a paleontologist specializing in ancient elephants at the University of Sheffield in England.
Colossal's long-term goal is to use artificial wombs to inseminate animals, a highly technical task. The company notes that its research on elephant cells could help current conversational efforts, such as potential treatments for a type of herpes that kills young elephants. In fact, the company hopes to make money by licensing or selling some of the technology it develops.
“It's not bringing back the mammoth, it's saving endangered species,” Church said. “It's creating useful technology for conservation and climate change.”
But the biggest threats elephants face are poaching, habitat destruction and other conflicts with humans, Cobb said. “How can a better understanding of cell biology help?”
What if they get destroyed again?
One of Colossal's overarching arguments for bringing back the mammoth is climate change. Scientists at the company say future Arctic herds could prevent permafrost from melting and releasing carbon into the atmosphere, which warms the atmosphere.
“Those are a lot of reasons to restore that environment to what it was,” Church said. “This is the missing keystone species for that.”
And then there's this philosophical question: Is a bioengineered mammoth really a mammoth? Or a furry elephant that can withstand the cold?
“It's creating a whole new organism,” Herridge said. What killed off the woolly mammoth is still an open question, he added: Did humans overhunt them or was it the natural end of the last Ice Age? If the answer is the latter, then the Arctic may be unsuitable for a resurrected creature, whatever you want to call it.
“I want to see a mammoth alive,” he said. “I would absolutely love a time machine where I could go back to the Ice Age and see a herd of mammoths being mammoths in the landscape where they originated.”
“But that's all gone.”
