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The last known Tasmanian tiger—the top predator of the southern Australian island—died in 1936. But the U.S.-based bioscience company Colossal wants to bring back the species from extinction.
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Two years after announcing its plans to revive the canine-like marsupial, the company says that it’s almost finished its reconstruction of the animal’s genome.
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Once completed, Colossal says it’ll rely on the eggs of its closest relatives—carnivorous marsupials in the family Dasyurid—to bring the first thylacines back from oblivion.
On September 7, 1936, after receiving special protected status by the Australian government only months earlier, the last known thylacine—more commonly known as the Tasmanian tiger—died at the Beaumaris Zoo in Hobart, Tasmania. While many expeditions have scoured the southern Australian island for signs of the endemic marsupial, none have returned with credible evidence of its continued survival.
In the 90 years since its extinction, the effects of the Tasmanian tiger’s absence have been acutely felt. That’s because this canine-looking marsupial was actually the island’s top predator, and kept disease in check by preying on weaker animals while also hunting non-native species. Since its extinction—largely caused by human predation and habitat destruction—the incidences of wildfires, invasive species, and disease have only increased. If the Tasmanian tiger could be reintroduced into its natural habitat, the ecological benefits could be enormous.
At least, that’s the argument put forward by the Dallas-based company Colossal Biosciences, which aims to return species from extinction. While its most high-profile de-extinction case involves the return of the woolly mammoth, the company has also partnered with environmental groups to strengthen the genomes of existing species, such as the American bison. Now, Colossal says that it has reconstructed 99.9 percent of the Tasmanian tiger’s genome, leaving only 45 gaps that they say will soon be closed.
The genome of thylacine was first sequenced back in 2017 from a 108-year-old thylacine pouch, but the attempt left behind many genetic gaps. Colossal says they’ve filled many of those gaps using genetic material gathered from a 120-year-old thylacine tooth.
“Most ancient samples preserve DNA fragments that are on the order of tens of bases long,” University of Melbourne’s Andrew Pask, a member of Colossal’s scientific advisory board, told New Scientist, “hundreds if we are lucky. The sample we were able to access was so well preserved that we could recover fragments of DNA that were thousands of bases long.”
The company, in partnership with Australian scientists, announced their de-extinction plans for the Tasmanian tiger back in August of 2022, and suggested that the first joeys could be born in six to ten years. Similar to Colossal’s plans to use African elephants as surrogates for a future woolly mammoth calves, the return of the Tasmanian tiger would require the recovered genome to be implanted into the egg of a Dasyurid—a family of carnivorous marsupials that are the thylacine’s closest living relatives. Once the egg develops into an embryo, a surrogate would then carry the Tasmanian tiger (or science’s closest approximation) to term. The first of these creatures would then be released on private land on the island until a stable population could be maintained.
Of course, de-extinction itself is a controversial idea—some conservationists urge that resources should instead be focused on the endangered species that are struggling to survive today. While the return of the woolly mammoth has raised serious suspicion, seeing as the species has been extinct for thousands of years, the demise of the Tasmanian tiger is much more recent and also a direct result of modern human civilization. Even if the thylacine is a more sympathetic candidate, some scientists have remained skeptical that such a technique is capable of creating the thousands of individuals needed to sustain a diverse genetic population.
It looks like we’re going to find out.
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