For millions of years, dog-like creatures with pouches roamed mainland Australia, New Guinea and Tasmania. These striped carnivores hunted birds, small rodents and even kangaroos. But when European colonizers arrived in the South Pacific in the 1800s and early 1900s, they considered these marsupials, called thylacines, to be pests. Encouraged by a government bounty, settlers began systematically killing the animals.
This week, the Texas-based genetics start-up Colossal Biosciences, which last year announced plans to de-extinct the woolly mammoth, revealed another ambitious new project to do the same with thylacines. The group is teaming up with scientists and investing in a laboratory dedicated to resurrecting thylacines in hopes of one day reintroducing them to rebalance Tasmania’s ecosystem.
The project has produced plenty of skepticism. Jeremy Austin, an evolutionary biologist from the Australian Centre for Ancient DNA, tells The Sydney Morning Herald's Liam Mannix that the idea is “a fairytale science.”
“It’s pretty clear to people like me that thylacine or mammoth de-extinction is more about media attention for the scientists and less about doing serious science,” Austin tells the Morning Herald.
The company is working in partnership with scientists at the University of Melbourne’s Thylacine Integrated Genetic Restoration Research Lab, which was established earlier this year with a $5 million gift. Colossal will invest an additional $10 million, per the Morning Herald, as well as provide equipment, lab access and staff to help the new lab accelerate thylacine de-extinction efforts.
How exactly do the scientists plan to bring an animal back from extinction? Very carefully. They’ll start by sequencing the thylacine’s genome from DNA that’s been preserved for decades. Next, they’ll complete the same process for one of the thylacine’s closest living relatives, a tiny marsupial called the fat-tailed dunnart.
After comparing the two genomes, the scientists intend to use gene-editing technology to make the DNA in a fat-tailed dunnart cell more closely match that of the thylacine. Their plan is to insert the cell’s nucleus into a fat-tailed dunnart’s egg, then stimulate embryonic growth.
This should, they say, lead to a thylacine-like embryo developing in either an artificial womb or a surrogate dunnart mother, where it would gestate for up to 42 days. If all goes to plan, a thylacine-like baby would then be born into the world. Researchers claim they could produce an animal that is roughly 90 percent thylacine within the next decade, though they eventually hope to develop an animal that is a 99.9 percent match, reports Scientific American’s Kate Evans.
In a literal sense, de-extinction is impossible, Ben Novak, lead scientist for de-extinction nonprofit Revive & Restore told Quanta Magazine's Yasemin Saplakoglu in May. “You can never bring something back that is extinct,” he said to the publication. Instead, most of these companies intend to create a proxy creature that can fill the extinct species’ role in the ecosystem, Quanta wrote.
If it succeeds at creating new thylacines, Colossal wants to work with conservation groups and Indigenous peoples to release the animals in Tasmania. The researchers believe that thylacines—which were once Tasmania’s top predator—could help address the overpopulation of animals like wallabies and kangaroos, as well as hunt sick animals to prevent diseases from proliferating.
"Our ultimate goal with this technology is to restore these species to the wild, where they played absolutely essential roles in the ecosystem,” says Andrew Pask, an epigeneticist at the University of Melbourne who is leading the project, to CNN’s Katie Hunt. “Our ultimate hope is that you would be seeing them in the Tasmanian bushland again one day.”
Hopes aside, a lot needs to go right for thylacines to once again prowl Tasmania, and the project has faced pushback from several different fronts. Some critics say the researchers need to be consulting Indigenous Australians now, before the project gets more deeply underway. Others have expressed concern that the headline-grabbing prospect of de-extinction will shift resources and attention away from the protection of still-living threatened species. Some scientists say it's simply impossible to tweak the fat-tailed dunnart's genome to resemble the thylacine's, since the two species are vastly different and disconnected by millions of years of evolution, writes Scientific American.
Still others worry about the treatment of the animals used throughout the research project, as well as the eventual quality of life of any proxy thylacines that actually come to fruition. Some scientists also hold ethical concerns around genome editing in general.
“The whole discourse is about bringing this animal back, but the welfare of the individual animals isn’t really talked about,” says Carol Freeman, an interdisciplinary researcher at the University of Tasmania, to Scientific American.