It’s been decades since the Australian thylacine, known as the Tasmanian tiger, was declared extinct and scientists say they have made a breakthrough in their research into ways to bring the carnivore back.
Colossal Biosciences said in a Thursday press release that the reconstructed thylacine genome is approximately 99.9% complete, with 45 gaps that they will attempt to close through additional sequencing in the coming months. The company also isolated long RNA molecules from a 110-year-old preserved head, which was skinned and preserved in ethanol.
“The thylacine samples used for our new reference genome are among the best-preserved ancient specimens my team has worked with,” said Beth Shapiro, Colossal’s chief science officer and director of the UCSC Paleogenomics Lab, where the samples were processed. “It’s rare to have a sample that allows you to push the boundaries of ancient DNA methods so far.”
Efforts to bring back the Tasmanian tiger
Preserving a complete Tasmanian tiger head meant scientists could study RNA samples from several key tissue areas, including the tongue, nasal cavity, brain and eyes. It will allow researchers to determine what a thylacine might taste and smell, along with what kind of vision it had and how its brain worked, according to Andrew Park, a member of Colossal’s Scientific Advisory Board and a researcher at the University’s TIGRR Lab from Melbourne. .
“Every day we get closer to being able to put the thylacine back into the ecosystem – which of course is also a great conservation benefit,” Pask said.
Pask, in conversation with 60 minutes Earlier this year, researchers teamed up with the Tasmanian tiger’s closest living relative – a small marsupial called the fat-tailed dunnart – as a way to bring the animal back.
“But that little dunnart is a ferocious carnivore, even though it is very, very small,” Pask said. “And it’s a really good surrogate for us to be able to do all these operations.”
Scientists compared the DNA of the dunnart and the thylacine, Pask told 60 Minutes. From there it’s a matter of going in and editing the DNA to turn a fat-tailed Dunnart cell into a thylacine cell.
Colossal Biosciences said Thursday that it has engineered more than 300 unique genetic changes into a thin cell, making it “the most edited animal cell to date.”
“We are really pushing the boundaries of de-extinction technologies,” Pask said, “from innovative ways to find the regions of the genome that drive evolution, to new methods of determining gene function. We are in the best place ever to rebuild this species using the most thorough genome resources and the best-informed experiments to determine its function.”
Efforts to promote the revival of the Tasmanian tiger are not limited to Australia. Last year, scientists extracted and sequenced RNA of a 130-year-old specimen of the Tasmanian tiger, preserved at room temperature in the Swedish Museum of Natural History.
How the Tasmanian Tiger Died
Thylacines roamed Tasmania for thousands of years. Despite the name Tasmanian tiger, the carnivores were marsupials, such as kangaroos, koalas and Tasmanian devils.
The local government paid bounties in the late 19th century to hunters who offered Tasmanian tiger carcasses because the animals had eaten farmers’ sheep, 60 Minutes previously reported. By the mid-1930s, the Tasmanian tiger population had dwindled to a single thylacine at the Beaumaris Zoo in Hobart, the capital of Tasmania. It died there in 1936.
Australia has similarly allowed the culling of kangaroos, thereby approving it death of thousands of kangaroos over the years. Officials have said the kangaroo population was eating through grassy habitats of endangered species. Officials have also warned in the past that there is not enough food available to sustain large kangaroo populations.
