(CNN) — Almost 100 years following its extinction, the Tasmanian Tiger might live once more. Scientists want to resurrect the carnivorous striped marsupial, officially known as the thylacine, that used to roam the Australian bush.
The ambitious project will take advantage of advances in genetics, ancient DNA recovery and artificial breeding to bring the animal back.
“We would strongly advocate 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 University of Melbourne professor and director of the Genetic Restoration Research Laboratory. Integrada del Tilacino, who leads the initiative.
“This technology offers the opportunity to correct this and might be applied in exceptional circumstances where key 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 audacious, $15 million project to bring back to the mammoth lanudo in an altered form.
The size of a coyote, the thylacine disappeared regarding 2,000 years ago from virtually everywhere except the Australian island of Tasmania. As the only marsupial apex predator to have lived in modern times, it played a key role in its ecosystem, but that also made it unpopular with humans.
European settlers on the island in the 1800s blamed thylacines for livestock losses (although, in most cases, feral dogs and poor human habitat management were to blame), and hunted the shy and semi-nocturnal Tasmanian tigers to the point of extinction.
The last thylacine to live in captivity, named Benjamin, died from exposure in 1936 at Beaumaris Zoo in Hobart, Tasmania. This monumental loss occurred shortly following the thylacines were granted protection status, but it was too late to save the species.
genetic model
The project involves several complicated steps that incorporate cutting-edge science and technology, such as gene editing and building artificial wombs.
First, the team will build a detailed genome of the extinct animal and compare it to that of its closest living relative, a mouse-sized carnivorous marsupial called the fat-tailed dunnart, to identify differences.
“Then we take living cells from our dunnart and edit their DNA at each place where it differs from the thylacine. Basically, we’re engineering our dunnart cell to become a Tasmanian tiger cell,” Pask explained.
Once the team has successfully programmed a cell, Pask said stem cells and reproductive techniques involving dunnarts as surrogates would “turn that cell back into a living animal.”
“Our ultimate goal with this technology is to restore these species to the wild, where they played an absolutely essential role in the ecosystem. So our ultimate hope is that one day you’ll see them once more in the bushlands of Tasmania,” he said.
The fat-tailed dunnart is much smaller than an adult Tasmanian tiger, but Pask said all marsupials give birth to tiny young, sometimes as small as a grain of rice. This means that even a mouse-sized marsupial might serve as a surrogate mother for a much larger adult animal like the thylacine, at least in the early stages.
Reintroducing the thylacine to its former habitat would have to be done very cautiously, Pask added.
“Any release like this requires studying the animal and its interaction in the ecosystem over many seasons and in large areas of closed terrain before considering a full reconstruction,” he said.
The team hasn’t set a timeline for the project, but Lamm said he thought progress would be faster than efforts to bring back the woolly mammoth, noting that elephants take much longer to gestate than dunnarts.
The techniques might also help living marsupials, such as the Tasmanian devil, avoid the fate of the thylacine as they deal with intensifying wildfires as a result of the climate crisis.
“All of the technologies we are developing to end the extinction of the thylacine have immediate conservation benefits, right now, to protect marsupial species. Frozen tissue biobanks have been collected from living populations of marsupials to protect once morest fire extinction.” Pask said via email.
“However, we still lack 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.”
hybrid animals
The way forward, however, is not simple. Tom Gilbert, a professor at the GLOBE Institute at the University of Copenhagen, said there are significant limitations to eliminating the extinction.
Recreating the complete genome of a lost animal from the DNA contained in old thylacine skeletons is extremely challenging, and therefore some genetic information will be missing, explained Gilbert, who is also director of the Center for Evolutionary Hologenomics at the National Research Foundation. from Denmark. He has studied the resurrection of the extinct Christmas Island rat, also known as the Maclear rat, but is not involved in the thylacine project. The team won’t be able to exactly recreate the thylacine, but will instead end up creating a hybrid animal, an altered form of 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 in the lost form. There will always be some parts that cannot be changed,” Gilbert said by email.
“They will have to choose what changes to make. And therefore the result will be a hybrid.”
It’s possible, he said, that a genetically imperfect hybrid thylacine might have health problems and not survive without a lot of help from humans. Other experts question the very concept of spending tens of millions of dollars on attempts to reverse extinction when so many living animals are on the brink of extinction.
“To me, the real benefit of any extinction reversal project like this is how amazing it is. Doing it seems very justified to me simply because it will get people excited regarding science, nature and conservation,” Gilbert said.
“And we sure need that in the wonderful citizens of our world if we’re going to survive into the future. But…do the stakeholders realize that what they’re getting won’t be the thylacine but some imperfect hybrid? is that more people are disappointed (or) feel cheated by science”.
