Scientists and startups are promoting a de-extinction rebellion


A diorama depicting a woolly mammoth standing on a green tundra beneath a blue sky.
Image Credit: Flickr/Rob Pongsajapan

In July of 1936 the ​​thylacine, better known as the Tasmanian tiger, was granted protection status in Australia. Two short months later, the last known ​​thylacine died of neglect at the Beaumaris Zoo in Hobart, the capital of Australia’s island state of Tasmania.


5,000 ​​thylacines once roamed Tasmania until the last known wild one was shot by a farmer, Wilf Batty in Mawbanna in April 1930.


These animals were hunted to extinction for the false belief that they preyed on sheep. Prior to the 30s, a government bounty was awarded to those who hunted thylacines. Officially enacted by the Parliament in 1888, the bounty stood until the animal was so rare that only one or two were caught a year.


Before they were eradicated, the animal was around for 2 million years. Now with that number at zero, the “de-extinction” company Colossal Biosciences wants to take on a multimillion-dollar project to genetically resurrect the Thylacinus cynocephalus.


Resurrecting the thylacine is the second ambitious project for the Dallas-based company, which previously announced plans to bring back the woolly mammoth. Colossal is perhaps the most aggressive example of the steps scientists are taking to save species on the brink of extinction or revive older species that have gone extinct.


But they're not the only ones. Groups like Revive and Restore (a FootPrint Coalition Science Engine partner) are part of a broad push from scientists around the world to use the latest in techniques in genetic programming and cloning to... revive and restore a number of extinct and endangered species.


Little is known about the behavior of the thylacine, as no formal study of wild individuals was done prior to their extinction. Also known as the Tasmanian wolf, the dog-like creature once roamed coastal mainland Australia, New Guinea, and Tasmania.


It was famously “not a feline,” as, during colonization, Europeans mistakenly labeled it as a cat. Rather, it is a darkly-striped rare marsupial, with sandy to gray fur. With similar DNA to modern kangaroos, it was described by Australian researchers as a “dingo or dog with a pouch.”


"Whatever you call it, this mythically beautiful carnivorous marsupial was a true masterpiece of biological advancement," the company says of the project. "Yet, the story of its extinction is a tragedy of human interference and aggression."


While the thylacine’s extinction is likely primarily due to human hunting, research led by University of Melbourne bioscientist Andrew Pask in 2017 found that the creature also lacked genetic diversity.


"The population today would be very susceptible to diseases, and would not be very healthy" if it still existed, Pask said in 2017. Later that year, Pask led a project to sequence a thylacine’s genome, the necessary first step on the path to de-extinction.


In March of this year, Pask and his team received a $5 million philanthropic gift to set up the Thylacine Integrated Genetic Restoration Research lab, accurately acronymized as the TIGRR lab. Last week, it was announced that the team partnered with the Texas tech company to revive the almost one-hundred-year extinct marsupial.


Now, Pask and his team of researchers at Colossal Biosciences are “determined to give the thylacine a second chance at life.”


An illustration of two Thylacine "Tasmanian Tigers". The fox-like animals have distinctive stripes across their lower back and tails.
Image Credit: Flickr/The Biodiversity Heritage Library

How and why does Colossal plan to bring back the thylacine?


To combat its lack of genetic diversity, the research group plans to combine diverse DNA sources. They also aim to bring back a “good amount” of specimens in order to ensure a healthy diversity of the species, Pask told NPR.


Throughout the 1990s, there were countless searchers to find the thylacine in the wilds of Tasmania and Victoria. Before Colossal, the biggest proponent of thylacine de-extinction was Professor Mike Archer, a former director of the Australian Museum who wanted to use DNA from preserved specimens in its collection.


According to the University College of London, previous research such as Archer’s has been put into cloning the Tasmanian tiger. However, cloning requires a living cell, thus these projects were abandoned due to the fragility of preserved specimens.


Instead, the team at Colossal is taking a different approach. Essentially, the team plans to create a hybrid animal that shares many characteristics with the thylacine. The marsupial belonged to the family Dasyurid, which includes other carnivorous marsupials like the Looney Tune-like Tasmanian devil and the numbat: the thylacine's closest relatives.


Using CRISPR gene editing technology, the team plans to splice recovered thylacine DNA into the Dasyurid genome. The altered nucleus will then be placed into the Dasyurid egg. Once it develops into an embryo, it would be implanted into a surrogate. The result will be an animal that is “99.9 percent thylacine” Pask said according to The Guardian.


This is a similar process the company plans to use in its de-extinction of the woolly mammoth, this time with an elephant surrogate.


Other than undoing the massive human mistake, one might ask, why in the world would researchers want to bring back long-extinct animals?


According to Pask, "The thylacine was the only apex predator in the Tasmanian ecosystem, so no other animal was able to fill its place once it was lost.”


He told NPR, that the loss of the thylacine dramatically impacted the Tasmanian devil, which was nearly wiped out due to disease. Throwing the entire ecosystem off balance, restoring the thylacine’s place in the food chain would "remove the sick and weak animals from the population to control the spread of transmissible diseases and also improve the genetic health of all the populations it impacts," Pask said.


The first cloned black-footed ferret, Elizabeth Ann, cradled in the hands of a scientist wearing protective rubber gloves.
Image Credit: Revive and Restore


How else can CRISPR also be used to protect species?


CRISPR is often the source of much scientific controversy, and while some scientists argue that we should instead be focusing on conserving endangered species instead of resurrecting extinct ones, others like evolutionary biologist and How to Clone a Mammoth author Beth Shapiro argue that the gene editing technology can be used as a “genetic booster shoot,” for at-risk species.


“We're facing a crisis — a conservation, biodiversity crisis. This technology might be a very powerful new weapon in our arsenal against what's going on today. I don't think we should dismiss it out of fear,” Shapiro told NPR.


In an effort to save the endangered black-footed ferret, the animal was cloned in 2021. Previously considered extinct, the ferret, named Elizabeth Ann, represents the first successfully cloned endangered species.


The ferret has not been the only attempt wielding CRISPR for conservation efforts. In 2020, a team at UC Davis cloned a fish that strikingly resembled an endangered Delta smelt. The black-footed ferret was the ambition of the nonprofit Revive & Restore, a wildlife conservation organization that advocates for the use of biotechnologies to genetically rescue endangered and extinct species.


Since Elizabeth Ann, the group has also improved the biodiversity of Przewalski's horse, coral, and more. Separately, research has been put into bringing back other animals, especially birds. Virginia Tech has a project underway to resurrect the only native parrot species to the U.S., the Carolina parakeet, and there has even been interest at Revive & Restore in bringing the dodo back to its native and now protected habitat by way of pigeon surrogate.


Illustration of a dodo bird
Image Credit: Wix

What other efforts are out there?


Nevertheless, there are less sci-fi ways to conserve the nearly-extinct, endangered, and threatened species that walk our Earth today.


One example is by way of the Endangered Species Act (ESA). Species listed under the ESA are not only federally protected, but conservation scientists develop and implement recovery plans for listed species.


These plans are roadmaps that outline tasks required to restore and secure self-sustaining wild populations. They vary based on species and include ideas for eliminating existing threats, enhancing or restoring habitats, identifying and reducing human-related harms, and implementing assessments of health, reproduction, and survival.


A recently released recovery plan for the humpback whale also includes the need for research to better understand the link between population decline and ocean conditions caused by climate change.


The humpback whale, which was once critically endangered, has been recovering and at present, is rated Least Concern on the International Union for Conservation of Nature’s (IUCN) Red List.


However, when species are rated more severely, programs such as captive breeding are necessary. Captive breeding has saved several animals from extinction. The most recent success stories include the Peregrine falcon (the fastest animal in the world) and the previously thought-to-be-extinct Mallorcan midwife toad.


De-extinction efforts may not directly take funding from conservation efforts like these, but some scientists wonder if they remove attention from animals at-risk now. The scientific community is fairly mixed on the idea as a whole.


Evidently still, some researchers believe that if once extinct, an animal leaves an ecological hole that none other can fill, de-extinction might be the answer. There is also the moral argument for de-extinction. Some scientists, like Axel Newton of the TIGRR Lab, believe that because many extinct animals are the direct result of human abuse, like in the case of the Tasmanian tiger, de-extinction is our responsibility.


“I think we have an obligation to do everything in our power to bring back this remarkable animal, particularly as our forebearers were the direct cause of its disappearance,” the evolutionary biologist said. “However, we also have an ethical and moral responsibility to ensure that the animal we resurrect is a 99%+ thylacine and not an almost-thylacine hybrid.”


Colossal plans to bring woolly mammoth calves into the world in the next four to six years. While the thylacine timeline has yet to be revealed, the Tasmanian tiger’s gestation period of up to 42 days is a lot shorter than that of the elephant-mammoth hybrid, which takes two years. Thus, the company CEO Ben Lamm, says the thylacine proxy will likely be the first animal to be “brought back.” If not before the woolly mammoth, in at most 10 years' time, Pask, who has more conservative estimates, told BBC.


Even if the team is unsuccessful in bringing back the thylacine, Pask says their research could prove worthwhile to preserve the genetic diversity of the growing list of threatened marsupials that could, like the Tasmanian tiger, be completely wiped out.



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