The ambitious project will harness advances in genetics, ancient DNA recovery and artificial breeding to bring the animal back. “We would argue strongly that first and foremost we need to protect our biodiversity from further extinctions, but unfortunately we are not seeing a slowdown in species loss,” said Andrew Pask, a professor at the University of Melbourne and head of Thyacine Integrated. Genetic Restoration Research Laboratory, leading the initiative. “This technology offers an opportunity to correct this and could be applied in exceptional cases where keystone species have been lost,” he added. The project is a collaboration with Colossal Biosciences, founded by tech entrepreneur Ben Lamm and Harvard Medical School geneticist George Church, who are working on an equally ambitious, if not more daring, $15 million project to bring back the woolly mammoth in an altered form. About the size of a coyote, the thylacine became extinct about 2,000 years ago almost everywhere except the Australian island of Tasmania. As the only modern marsupial apex predator, it played a key role in its ecosystem, but this also made it unpopular with humans. European settlers on the island in the 1800s blamed thylacines for animal losses (although, in most cases, feral dogs and mismanagement of human habitats were actually the culprits) and hunted the shy, nocturnal Tasmanian tigers to the point of extinction . The last thylacine living in captivity, named Benjamin, died of exposure in 1936 at Beaumaris Zoo in Hobart, Tasmania. This monumental loss occurred shortly after thylacines were given protected status, but it was too late to save the species. The project involves many complex steps that incorporate cutting-edge science and technology, such as gene editing and the construction of artificial wombs. First, the team will construct a detailed genome of the extinct animal and compare it to that of its closest living relative — a mouse-sized carnivorous marsupial called a fat-tailed dunnart — to spot differences. “We then take live cells from our dunnart and edit their DNA at every point where it differs from the thylacine. We’re essentially engineering the dunnart cell to become a Tasmanian tiger cell,” explained Pask. Once the team successfully reprograms a cell, Pask said stem cells and breeding techniques involving dunnarts as surrogates will “turn that cell back into a living animal.” “Our ultimate goal with this technology is to reintroduce these species into the wild, where they played absolutely essential roles in the ecosystem. So our ultimate hope is that you’d see them back in the Tasmanian bush one day,” he said. The fat-tailed Dunnart is much smaller than an adult Tasmanian tiger, but Pask said all marsupials give birth to tiny cubs, sometimes as small as a grain of rice. This means that even a mouse-sized marsupial could serve as a surrogate mother for a much larger adult such as a thylacine, at least in the early stages. Reintroducing the thylacine to its former habit should be done very carefully, Pask added. “Any release like this requires studying the animal and its interaction in the ecosystem over many seasons and over large areas of enclosed land before you consider a complete roll-out,” he said. The group has not set a timeline for the project, but Lamm said he believed progress would be faster than efforts to bring back the woolly mammoth, noting that elephants take much longer to conceive than Dunnarts. The techniques could also help living marsupials, such as the Tasmanian devil, avoid the thylacine’s fate as they battle intensifying wildfires as a result of the climate crisis. “The technologies we are developing for thylacine removal all have direct conservation benefits — at this time — to protect marsupial species. Biobanks of frozen tissue have been collected from living populations of marsupials to protect against wildfire extinction,” said Pask via EMAIL ADDRESS. “However, we still don’t have the technology to take that tissue — create marsupial stem cells — and then turn those cells into a living animal. That’s the technology we’ll develop as part of this project.” The way forward, however, is not cut and dried. Tom Gilbert, a professor at the University of Copenhagen’s GLOBE Institute, said there are significant limitations to de-extinction. Reconstructing the complete genome of a lost animal from DNA contained in old thylacine skeletons is extremely challenging, and so some genetic information will be missing, explained Gilbert, who is also director of the Center for Evolutionary Holonomics at the Danish National Research Foundation. He has studied the resurrection of the extinct Christmas Island rat, also known as Maclear’s rat, but is not involved in the thylacine work. The team won’t be able to recreate the thylacine exactly, but will end up creating a hybrid animal, a modified form of the thylacine. “It is unlikely that we will get the complete genome sequence of the extinct species, so we will never be able to completely recreate the genome of the lost form. There will always be some parts that cannot be changed,” Gilbert said via email. “They will have to choose what changes to make. And so the result will be a hybrid.” It’s possible, he said, that a genetically imperfect hybrid thylacine could have health problems and not survive without much help from humans. Other experts question the very concept of spending tens of millions of dollars on de-extinction efforts when so many living animals are on the brink of extinction. “To me the real benefit of any release project like this is the awesomeness of it. I feel very justified in doing it just because it’s going to get people excited about science, about nature, about conservation,” Gilbert said. “And we certainly need it in the wonderful citizens of our world if we are to survive in the future. But…do those concerned realize that what they will get is not the thylacine but some imperfect hybrid? What do we do” We don’t need even more people to become disillusioned (or) feel cheated by science’.
