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The plan to bring ‘a dingo with a pouch’ back from extinction : NPR


Now extinct, a Tasmanian tiger (thylacine) was seen in the Hobart Zoo in Tasmania in 1933.

Universal Historical Archive / Universal Image Group via Getty Images


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Universal Historical Archive / Universal Image Group via Getty Images


Now extinct, a Tasmanian tiger (thylacine) was seen in the Hobart Zoo in Tasmania in 1933.

Universal Historical Archive / Universal Image Group via Getty Images

If you haven’t heard of the Tasmanian tiger, it’s not because it’s not worth discussing: it’s famous not as a cat but as a dog-like marsupial, a carnivorous animal that humans hunted down to extinction level. The last known specimen died in the zoo in 1936.

Now the “near-extinct” company Colossal Biosciences wants to genetically revive the Tasmanian tiger, also known as thylacine (Thylacinus cynocephalus) or the Tasmanian wolf.

“Whatever you call it, this beautiful, mythical marsupial is a true masterpiece of biological progress,” the company said of project. “However, the story of its extinction is a tragedy of human intervention and invasion.”

Thylacine has stripes that are characteristic and rare in the animal kingdom, having abdominal sacs in both females and males. Australian researchers have called it “dingo with a bag” or “a dog with a bag” – but its DNA also has much in common with kangaroos.

Colossal, previously planned to broadcast resurrect woolly mammothsintended to give thylacine “a second chance at life.”

Here is a summary of some of the big questions raised by the project:

Does Thylacine have the ability to resurrect?

Humans have been blamed for the animal’s extinction, especially after a bounty program was set up in Tasmania to protect sheep and other animals. But in 2017, Andrew Pask, a professor of biological sciences, led research that discovered thylacine also lacks genetic diversity.

“Today’s population would be very susceptible to disease and would not be very healthy” if it persisted, Pask said in 2017.

Pask is now part of Colossal’s new project to bring back thylacine. When asked if his views on its viability had changed, he said via email that the plan would incorporate diverse DNA sources.

“We have now decoded numerous thylacine specimens and hope to continue to do so in this new partnership with Colossal,” Pask said in an email to NPR. “Even species with low genetic diversity can be returned to healthy populations if they are managed properly.”

The goal, he said, is to bring back “a good number” of animals to help ensure healthy diversity in the new population. And while thylacine is seen as struggling in the wild, any new populations will be closely watched, he noted.

How will the animals be created?

For one thing, it’s not cloning.

“Clone is a very specific scientific process. That process requires a living cell,” says evolutionary biologist Beth Shapiro of the University of California, Santa Cruz. tell NPR When it comes to resurgence, the mammoth earned new currency in 2015.

Instead, Colossal plans to essentially create a hybrid animal, with many of the traits of a Tasmanian tiger. Its scientists will use CRISPR gene-editing technology to insert recovered fragments of thylacine DNA into the genomes of Dasyurids – a family of carnivorous marsupials such as pangolins and Tasmanian devils that are their closest relatives. animals are extinct.

The altered nucleus is then inserted into a Dasyurid egg – and when it develops into an embryo, it is implanted in a surrogate.

How will Thylacine affect Tasmanian habitat?

“Thylacine is the only apex predator in the Tasmanian ecosystem, so no other animal can fill its place once it’s lost,” Pask said. “We’ve seen the impact of this on the Tasmanian devil population, which has been almost wiped out by a tumorous disease of the face.”

The return of crested carnivores, he added, would “remove sick and ailing animals from populations to control the spread of infectious diseases and also improve the genetic health of animals.” all populations it affects”.

Pask says thylacine has played that role for thousands of years and its return could now restore balance to the entire ecosystem in Tasmania.

When can the first embryos be created?

It could come as early as the next few years. By comparison, Colossal hopes to bring its first mammoths to the world within the next five or six years, using elephant substitute.

The timeline for thylacine has yet to be revealed. But Ben Lamm, founder and CEO of Colossal, noted via email that the Tasmanian tiger’s expected gestation period of up to 42 days would be much shorter than that of a mammoth hybrid.

“A large portion of our mammoth’s life is based on the nearly two-year gestation period of calves,” Lamm said. “I think it’s probably safe to assume that the thylacine proxy might have been one of the first animals to be brought back.”

Will the Tasmanian tiger ever be brought to mainland Australia?

“Whether we’ll bring thylacine back to land is a really interesting question,” said Pask, noting that the animal was thought to have been found in Australia until 2,000 or 3,000 years ago. .

“If thylacine is effective in eradicating some of our invasive pests such as rabbits, cats and foxes – bringing them back to land could have huge conservation benefits for our communities,” he said. other ecosystems”.

However, he added, such an idea would have to be considered and studied in captivity before it could be considered for wider release.

Sure, they can – but should they?

Promoting genetic diversity and helping ecosystems are reasons Beth Shapiro cited when speaking in favor of the use of gene editing. But while Colossal focuses on trying to bring back extinct animals, Shapiro suggests that the focus should be on the wildlife we’re currently struggling with, such as the mink. black foot (used to be ) once thought to be extinct).

She told NPR in 2017. “Perhaps we can use this technology to give those populations a little bit of a genetic boost and maybe a fighting chance against diseases that are emerging. kill them, biodiversity crisis. This technology could be a very powerful new weapon in our arsenal against what is happening today. I don’t think we should get rid of it out of fear. “



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