Inside the Plan to Resurrect Australia's Extinct Tasmanian Tiger
Wilfred Batty's sister had just sat down to eat lunch when, out the window, she saw a shadow flicker across the yard. A beast, slender and wolf-like, prowled around the chicken pens.
The creature, a thylacine, had been the cause of great trouble for Batty and other local farmers in Tasmania, Australia — snatching fowl in the middle of the night and, on one occasion, unceremoniously entering a hut at dusk, frightening the campers within. A thrown boot had startled it, causing it to slink away into the dark.
It would not be so lucky this time. Batty and his son grabbed their guns, burst out the door and gave chase. As Batty approached, the thylacine — or "Tasmanian tiger" — turned tail and fled, darting behind a garage. Not wanting it to escape again, the farmer unloaded his rifle, fatally hitting the animal in the shoulder. It collapsed in his yard.
For decades, the number of tigers had been dwindling, mostly due to hunting, but Wilfred Batty couldn't have known that on this afternoon, May 13, 1930, his kill would go down in history. It was, officially, the last Tasmanian tiger, or thylacine, to be killed in the wild. The species would be rendered extinct with the death of Benjamin, a captive tiger at Hobart Zoo, in 1936.
What if we could reverse this? What if, through the power of revolutionary gene-editing technology, we could bring the tiger back from the dead and repopulate the Tasmanian wilderness? Andrew Pask, a professor of evolutionary biology at the University of Melbourne, and his team are attempting to do just that, with plans to "de-extinct" the thylacine in the next decade.
The technology to resurrect the dead, de-extinction advocates will tell you, already exists. It's just a matter of funding and focus. That's where Colossal, a de-extinction and gene-editing startup with plans to bring back the woolly mammoth by 2027, comes in.
On Aug. 16, Colossal announced that its second de-extinction project will be the thylacine, and, through $10 million in funding over the next three years, it will be supercharging Pask's research, helping to further develop technologies necessary to resurrect the tiger.
"The challenges ahead of us are engineering challenges, they're not science challenges," said Ben Lamm, co-founder of Colossal.
Pask's laboratory has published extensively on marsupial genetics and was the first to decode the thylacine genome back in 2017. Earlier this year, it received $3.6 million ($5 million Australian) in philanthropic funding to establish the Thylacine Integrated Genetic Restoration Research, or TIGRR, Lab in Melbourne.
De-extinction and rewilding of the striped marsupial is the headline goal, but along the way the lab hopes to generate new conservation techniques and create technologies that can help Australia's beleaguered marsupial populations as they face the increasing threat of climate change, habitat loss and environmental degradation. With Colossal on board, work to revive the species can accelerate rapidly and, within the next decade, the thylacine could prowl the wilds of Tasmania once again.
It may even prove easier to bring back than a mammoth.
Two mammoth tasks
Colossal made waves in September 2021, announcing its plan to resurrect woolly mammoths — or, more accurately, an approximation of woolly mammoths — and introduce them to the Arctic within about five years.
The company's idea is to cut-and-paste woolly mammoth DNA into Asian elephants, adding in genes that confer cold resistance to the pachyderms. If successful (and after achieving regulatory approval), a herd of these hybrids would be released into the Arctic tundra where they could remodel the landscape, helping to prevent the vast stores of carbon in the soil from being released.
Colossal is bankrolled by investment groups and co-founded by Lamm and George Church, a Harvard and MIT professor who has been dubbed the "father of synthetic biology." Church has a long history working with CRISPR, a technology that allows scientists to edit DNA with almost-unmatched precision. It's CRISPR that much of the mammoth work will hinge on, and Church's team is continuing to develop methods that will allow the wide-scale changes in DNA necessary to revive long-dead creatures. It's this expertise that will complement Pask's work on thylacine de-extinction.
For Lamm, adding the thylacine project to the company's mammoth ambitions is about bringing two projects together to help drive them both forward. He says the thylacine research is "almost an exact opposite" of the mammoth research.
For instance, the thylacine has only been extinct for around 90 years, whereas the last mammoths roamed the Earth some 4,000 years ago. This makes it much easier to get a complete DNA sequence from the thylacine. Mammoth DNA is far more degraded and — even though George Church is considered a guru in this space — harder to piece back together.
Overcoming the challenges in one Lazarus project will support progress in the other. So, even with the announcement Colossal is taking on thylacine resurrection, it's not as if the mammoth work is taking a backseat. Lamm says there are now over 35 employees at Colossal working on its mammoth project and the team have reconstructed 54 genomes.
"I still have incredible love for the mammoth," he laughs. "I want to make that clear."
Pask, on the other hand, is all about the thylacine. The last time I visited his office, pre-pandemic, it was chock full of tiger paraphernalia, clippings and pictures (and, if I recall, one figurine of Jurassic Park's John Hammond). I can't think of too many people who'd be more thrilled to welcome the thylacine back to Earth — but this isn't an all-or-nothing game. It's not just about resurrection. Whenever we discuss the realities of bringing a species back from the dead, Pask's pragmatism shines through. He knows resurrecting the tiger will be tough.
But Pask, and his TIGRR lab, have a plan.
Resurrecting the Tasmanian tiger
The idea to resurrect the thylacine is not a new one. When biologist Mike Archer was appointed director of the Australian Museum in 1999, he had grand plans to clone the creature by extracting DNA from the museum's specimen collection. The project was scrapped in 2005 because the quality of the DNA was too poor to work with.
"In the early 2000s, this wouldn't have worked," notes Lamm. Today, though, he believes it's a different story. Scientists like Pask are looking at entirely new methods, including CRISPR gene-editing, which just wasn't possible two decades ago.
Here's the plan.
The first step is to unravel the mysteries of thylacine DNA. This step was completed in 2017 by Pask's lab. With this, the researchers have the thylacine "recipe" or "blueprint" — the DNA instructions needed to build a thylacine.
Next, they will need to take cells from a close living relative, like the fat-tailed dunnart, a mouse-like marsupial that could fit in the palm of your hand. They also have the dunnart's DNA blueprint.
The theory here is that you need to identify all the differences between the dunnart DNA and the thylacine DNA. This is an active area of research requiring a ton of computing power and bioinformatics. But suppose they can pinpoint those differences (a huge supposition and one that's not guaranteed by any stretch); they will then take cells from the dunnart and, using the gene-editing tool CRISPR, build a thylacine cell. This is Pask's major focus right now.
"We're interrogating every single part of the thylacine genome," he says. "It's an expensive and time-consuming endeavor, but now we can figure out those essential [DNA] edits we need to make that thylacine."
Then, the hard part. The scientists will need to make an embryo that can then either be implanted into the pouch of another marsupial species (like a dunnart) or grown in a microfluidics chamber. If they can coax the embryo to grow, then they can remove it from the pouch to feed and care for it. This is still a long way from reality, but, if it succeeds, soon enough, you'll have something that resembles a full-grown thylacine.
It's not just about bringing the animal back once, either. The mark of success for Colossal, and Pask's lab, is rewilding. And rewilding requires many thylacines. "To bring a healthy population of thylacines back, you can't bring back one or five," Pask notes. "You're looking at bringing back a good number of animals that you can put back into the environment."
It sounds straightforward, but there's a lot of science to do. Teaming up with Colossal provides extra bandwidth for the TIGRR lab — and its sister lab in Texas — to work on the plan's outstanding problems in parallel. And the Colossal mammoth team will share its homework, too, to get through the decade of tinkering with genes ahead of the team.
"A lot of this is just purely grunt work" says Pask. "We just need people chipping away at every single aspect of these really big problems."
Whether they could, if they should
The specter of Ian Malcolm, Jeff Goldblum's eccentric and inimitable Jurassic Park mathematician, hangs over every de-extinction project (and pretty much every piece of popular science reporting on the topic, too).
His famous line, when discussing the merits of de-extincting dinosaurs for a theme park, goes: "Your scientists were so preoccupied with whether they could, they didn't stop to think if they should."
Colossal and its team of scientists and researchers seem to have thought through the could of de-extinction. The plans are in place; the road map laid out. They could de-extinct species. They are also cognizant of the should, attempting to bolster the argument that de-extinction research has real world benefits.
There are, they say, benefits that are likely to spin out of the de-extinction development phase for conservation today. For instance, Lamm notes the team is developing an "exopouch," a synthetic analog to a marsupial's pouch, which could be used to rear other species like the Tasmanian devil. Not all joeys (babies) survive to adulthood, but an exopouch might enable conservationists to save four or five times the number of joeys by nurturing them outside of their mother's care. And then there's the assisted reproduction technologies Pask is developing, which could aid in the creation of stem cell lines for other threatened marsupials, providing a gene bank to preserve species at a cellular level as a fail-safe.
However, other scientists are critical of these ideas, arguing that "de-extinction is unlikely to offer any real value to the overall conservation of biodiversity." There are no guarantees the grunt work will result in conservation wins, that CRISPR technology will be refined enough to make the necessary DNA edits or that the new technologies will have any impact.
There are other broader social and ethical issues to be worked through, too. Can we really grasp how a resurrected animal, or group of animals, will fare in today's world? Are we bringing them back to, effectively, doom them again? How will they feel? Will they experience pain? How does reintroducing them affect the Indigenous people of the land they're being returned to? As science and engineering for de-extinction accelerates, these questions will require answers.
And what of current conservation efforts? For now, most de-extinction work remains in the hands of biotech startups, funded by investment companies and philanthropists. But if these projects become "sexy" and begin attracting dollars away from ecology and conservation research, one model suggests it could lead to a net loss of biodiversity.
Hugh Possingham, a conservation biologist at the University of Queensland, offers an Australian perspective. "If funding de-extinction reduces investment in saving the species we have, then it doesn't make sense," he says. "If funding de-extinction does not compromise conservation funding, then it is an intriguing but high-risk activity."
It's a risk that Colossal, Lamm and Pask are taking. And if it works — and that remains a mighty, mighty if even with a fresh injection of cash — other resurrections may soon follow. But which ones?
"We've got a lot of work to do between these two species," says Lamm. "We'll think about future [projects] if we need to."
Updated Aug 16: Added context in final section above illustration.
Updated Aug 18: Provided additional context around the difficulty of resurrection in the second section.