The Tasmanian tiger could be resurrected from extinction

The ambitious project will leverage advances in genetics, ancient DNA recovery and artificial reproduction to bring the animal back to life.

“We strongly argue that first of all we need to protect our biodiversity from further extinctions, but unfortunately we are not seeing a slowdown in species loss,” said Andrew Pask, professor at the University of Melbourne and head of its Thylacine Integrated Genetic. Restoration Research Lab, which leads the initiative.

‘This technology offers the potential to correct this problem and could be applied in exceptional circumstances where fundamental species have been lost,’ he added.

About the size of a coyote, the thylacine virtually disappeared about 2,000 years ago everywhere except the Australian island of Tasmania. Being the only marsupial apex predator to live in modern times, it has played a key role in its ecosystem, but this also made him unpopular with humans.

European settlers on the island in the 1800s blamed the thylacines for livestock losses (although, in most cases, wild dogs and human habitat mismanagement were actually the culprits) and hunted the timid semi-nocturnal Tasmanian tigers to the point of extinction.

The last thylacine to live in captivity, named Benjamin, died from the exhibition in 1936 at the Beaumaris Zoo in Hobart, Tasmania. This monumental loss it occurred shortly after the thylacines were granted protection status, but it was too late to save the species.

Genetic project

The project involves several complicated steps that incorporate cutting-edge science and technology, such as gene editing and the construction of artificial uteri.

First, the team will build a detailed genome extinct animal and compare it to that of its closest living relative – a carnivorous mouse-sized marsupial called a fat-tailed dunnart – to identify the differences.

“We then take living cells from our dunnart and modify their DNA wherever it differs from the thylacine. We are essentially designing 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 “will return that cell to a living animal.”

'Precious' 1935 footage of the last known Tasmanian tiger released

“Our ultimate goal with this technology is to restore these species to the wild, where they have played absolutely essential roles in the ecosystem. So our ultimate hope is that someday you will see them again in the Tasmanian bush,” he said.

The fat-tailed dunnart is much smaller than an adult Tasmanian tiger, but Pask said all marsupials give birth to tiny little ones, sometimes as small as a grain of rice. This means that even a mouse-sized marsupial could act as a surrogate mother for a much larger adult animal like the thylacine, at least in the early stages.

Reintroducing thylacine to its previous habit should be done with great caution, Pask added.

“Any release like this requires studying the animal and its interaction in the ecosystem over many seasons and over large areas of fenced land before considering a full rewilding,” he said.

The team didn’t set a timeline for the project, but Lamm said he thought progress would be faster than efforts to bring the woolly mammoth back to life, noting that elephants take much longer to gestate than dunnarts.

The techniques could also help living marsupials, such as the Tasmanian devil, avoid the thylacine’s fate as they grapple with escalating forest fires due to the climate crisis.

“The technologies we are developing to extinguish thylacine all have immediate conservation benefits – right now – to protect marsupial species. Biobanks of frozen tissue have been harvested from living marsupial populations to protect themselves from extinction from fires,” he said. Pask stated by email.

“However, we still lack the technology to take that tissue – create marsupial stem cells – and then turn those cells into a living animal. This is the technology we will be developing as part of this project.”

Hybrid animals

The path forward, however, is uncut and dry. Tom Gilbert, a professor at the GLOBE Institute of the University of Copenhagen, said there are significant limitations to de-extinction.

Recreating the entire genome of a lost animal from the DNA contained in old thylacine skeletons is extremely challenging, and thus some genetic information will be missing, explained Gilbert, who is also director of the Center for Evolutionary Hologenomics at the Danish National Research Foundation. . He studied the resurrection of the extinct Christmas Island mouse, also known as Maclear’s rat, but is not involved in the thylacine project. The team won’t be able to exactly recreate the thylacine, but instead will end up creating a hybrid animal, an altered form of thylacine.

Scientists want to resurrect the woolly mammoth.  They just received $ 15 million to make it happen

“It is unlikely that we will get the entire 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 Gilbert said by email.

“They will have to choose which changes to make. And then the result will be a hybrid.”

It’s possible, he said, that a genetically imperfect hybrid thylacine could have health problems and might not survive without much help from humans. Other experts question the very notion of spending tens of millions of dollars on disinfection attempts when so many living animals are about to disappear.

“To me the real benefit of any de-extinction project like this is its beauty. Doing so seems very justified to me simply because it will thrill people about science, nature, 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 stakeholders realize that what they will get is not the thylacine but an imperfect hybrid? What do we do? Even more is needed. people are disappointed (or) feel deceived by science “.

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