It’s Jurassic Park all over again as scientists attempt to use gene-editing technology to resurrect the Tasmanian tiger or thylacine, a marsupial native to Australia that went extinct in the 1930s. The ambitious, $15-million project, being undertaken by scientists from Australia and the US, aims to reintroduce the animal to Tasmania, its native place, to revive the region’s ecological balance.

The project was announced by Texas-based Colossal Biosciences, behind last year’s Wolly mammoth resurrection project. The Tasmanian tiger project will be conducted with the University of Melbourne’s Thylacine Integrated Genetic Restoration Research Lab. Several big names, including actor Chris Hemsworth, a Colossal investor, has backed the project.

This is not the first time there has been an attempt to revive thylacines. Australian scientist Dr Michael Archer embarked on a journey to resurrect the animal in 1999 using cloning technology from a perfectly preserved museum specimen.Tasmanian tiger (Thylacinus cynocephalus) was the only Thylacinidae family animal to survive into modern times. A marsupial mammal, it raised young ones in a pouch.

Despite its Tasmanian tiger nickname because of the stripes on its back, the animal was a slow-paced carnivore that hunted alone or in pairs at night. The animal had sharp claws and a dog-like head and ate other marsupials, kangaroos, birds, and small rodents.

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The animal was widespread in the woods and grasslands of continental Australia between New Guinea in the north and Tasmania in the south. However, European colonisation of Australia changed the animal’s fate.

The animals were killed in large numbers with official authorisation for eating the poultry of farmers. Van Diemens Land Company in 1830 announced a bounty on the animal. In 1888, the Tasmanian Parliament passed an official bounty of £1 on thylacines.

Naturalist Harry Burrel published a series of photographs in the 1920s that showed thylacines catching poultry and other birds. The photographs explain the animal’s unpopularity among the public, even though the pictures’ authenticity was later questioned.

Competition with the Dingo is also considered as a reason behind its extinction.

In July 1936, after the last wild thylacine was killed between 1910 and 1920, the Australian government declared the animal a protected species. However, two months after the announcement, the last captive thylacine, Benjamin, died at Hobart’s Beaumaris Zoo. The animal was officially declared extinct in the 1980s.

Being at the top of the food chain, the Tasmanian tiger played an important role in balancing the region’s ecosystem by removing weak animals and maintaining species diversity. An apex predator, its disappearance from the food chain led to Trophic Downgrading — causal degradation in an ecosystem, occurring when a higher trophic-level animal is removed from the food chain, resulting in exponential growth or loss of other species.

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Trophic Downgrading also disrupts biogeochemical cycles, growth of invasive species, wildfires, and carbon sequestration.

As the only apex predator in its ecosystem, the thylacine’s absence also impacted the Tasmanian Devil, which was almost driven to extinction by a facial tumour disease. The thylacine would have stopped this by removing weak and sick animals from the ecosystem and eventually controlling transmission of diseases.

THE RESURRECTION

Despite the last living thylacine dying nearly 86 years ago, many young specimens and embryos have been preserved.

The de-extinction project will be led by University of Melbourne professor of Epigenetics Biosciences Dr Andrew Pask. The scientists will use a genome sequenced from a DNA from a 108-year-old specimen held at the Victoria Museum.

The scientists will compare this genome with the species’ closest living animal — the fat-tailed dunnart — and identify the differences. Once the differences are identified, the scientists will engineer the DNA of the living cell where it is different and bring the extinct species back.

Speaking to IndianExpress.com, Dr Pask said: “Once we have the engineered cells, we use stem cell technologies and cloning techniques to turn those cells back into a living animal. While all of these technologies already exist, this is the first time they will be developed for marsupials.”

A mouse-like species in the Dasyuridae family, the fat-tailed dunnart has an average body length of 2.4–3.5 inches and are among the smallest carnivorous marsupials.

Colossal said de-extinction would not be complete until a successful rewilding process to stabilise Tasmania’s fragile ecosystem

Colossal Co-founder and CEO Ben Lamm said: “The thylacine is a great candidate for de-extinction because it only went extinct in 1936 due to human hunting and the ecosystem we are looking to return it to is still intact. Furthermore, we have incredible tissue samples and genomes assembled as well as many additional pelts that are being sequenced for population genomics studies.”

While the scientists have not set a timeline, it is expected to take less time than the de-extinction of the Woolly mammoth, considering the longer gestation of elephants.

Lamm said the rewilding process needed to be carefully studied and executed with help for local governments, rewilding experts, conservation groups, indigenous peoples’ groups, and ecologists.

“We have started conversations with leading rewilding and conservation groups in Australia and Alaska as well as consultants that work with the local indigenous people groups in both Australia and the broader Arctic circle”

However, despite the praises, several scientists have raised concerns over the technology’s practicality.

Australian Centre for Ancient DNA Associate Professor Jeremy Austin told The Sydney Morning Herald that de-extinction was a fairytale science.

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He added that it was clear to people like him that mammoth or thylacine de-extinction was more about media hype for the scientists and less about serious science.

POSSIBILITIES AND CHALLENGES OF DE-EXTINCTION TECHNOLOGY

De-extinction is the method of creating an endangered or extinct species to revitalise the ecological diversity and balance that has shattered due to reasons that range from climate change to biodiversity loss. Cloning is the most widely used de-extinction method, but selective breeding and genome editing are also considered effective.

One of the first species to be resurrected was the Pyrenean ibex, a subspecies of the Spanish ibex, using somatic cell nuclear transfer. However, the baby ibex died within minutes of its birth due to a lung defect.

A co-operation between the Dutch Foundation and multiple universities — Tauros Programme — is currently working to resurrect aurochs, a cattle species similar to the wild ancestor of domestic cattle.

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Other de-extinction candidates are Maclear’s rat, an extinct large rat from the Christmas Island in the Indian Ocean, the passenger pigeon, a migratory bird from North America, and a plains zebra subspecies, the quagga.