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Scientists try to bring Australian ‘tiger’ back from extinction

Axel Newton, a research fellow at the University of Melbourne and a founding member of the Thylacine Integrated Genomic Restoration Research (TIGRR) lab, lifted cryogenically frozen human, mouse, and marsupial cell lines from their liquid nitrogen storage. The Australian lab has begun an endeavor to clone an extinct animal that was known as the Tasmanian tiger.Alana Holmberg/Oculi/For The Washington Post

MELBOURNE — The scientist reached into an enclosure in the biosciences building at the University of Melbourne and pulled out a dunnart — a mouse-sized marsupial with huge, inky black eyes. It latched its teeth onto developmental biologist Stephen Frankenberg’s finger. Frankenberg put it back, and it scampered into its home of egg cartons and native grasses.

The tiny creature seems an unlikely candidate for closest living relative of an apex predator. But it could be key to bringing the thylacine — also called the Tasmanian tiger — back from extinction.

The enclosure is part of the university’s newly established Thylacine Integrated Genetic Restoration Research (TIGRR) lab. A team of genetic scientists led by biosciences professor Andrew Pask is attempting to make the concept of “de-extinction” a reality. Over the coming decade, they plan to use gene editing to turn a dunnart cell into a thylacine cell and bring the long-dead creature into today’s world.

The goal invites an obvious reference. Pask doesn't mind.

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“I love Jurassic Park!” he said. “I love it.” He keeps a boxed figurine of John Hammond, the character in the 1993 film who creates the ill-fated park for de-extincted dinosaurs, in his office.

Critics call de-extinction projects expensive follies that distract from the real work of conservation and that could have unintended consequences. But Pask, unlike the fictional Hammond, says he has a conservationist’s ethos. Australia has the fastest rate of mammal extinction in the world, driven primarily by invasive species such as foxes and feral cats, and changing wildfire patterns. He hopes the scientific advances that will be necessary to restore the thylacine will help endangered animals still hanging on to survival.

“When people say, ‘Didn’t we learn anything from Jurassic Park?’ — well, it’s very different bringing back a velociraptor to a thylacine,” he said.

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Pask’s favorite vanished species was native to the island of Tasmania. The thylacine looked somewhat like a small wolf with a distinctive striped back, jaws that opened 90 degrees, and a pouch on its belly, like a kangaroo’s, for carrying young. The last known individual, named Benjamin, died in a Hobart zoo in 1936.

Here’s the plan to bring it back: First, turn dunnart cells into thylacine cells using gene-editing technology. Then use the thylacine cells to create an embryo, either in a petri dish or the womb of a living animal. Implant the embryo into a female marsupial such as a quoll, and watch the quoll give birth to a thylacine baby. When the baby is old enough to leave the quoll pouch, raise it into adulthood. Repeat and establish a healthy population, with the goal of releasing thylacines into the wild.

“It is certainly feasible,” said Owain Edwards, Environmental Synthetic Genomics group leader at the Commonwealth Scientific and Industrial Research Organization, who is not involved in the project. “Absolutely. What they’re proposing to do, can be done. What isn’t clear to anybody yet is: What exactly will result from it? Because it will never be a pure thylacine.”

Gene editing is different from another process with a foothold in the public imagination — cloning. Unlike in cloning, the cell that resulted from the TIGRR lab work would not contain an exact copy of a thylacine genome. It would be a part-dunnart, part-thylacine hybrid. “I don’t know whether it’s going to be 99 percent thylacine or 99.99 percent thylacine or 78 percent thylacine,” Pask said. “We will be able to bring back something.” The approach is similar to a US effort to de-extinct the woolly mammoth by editing elephant DNA.

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Paul Thomas, a molecular biologist with the University of Adelaide who is also not involved in the TIGRR lab, has doubts the extensive genome editing that would be required — he is reluctant to call it a de-extinction — will be feasible within the next decade. The dunnart and thylacine genomes have “probably hundreds of thousands — probably millions — of differences,” he said. “It’s an interesting approach, but it’s certainly going to be a long and difficult project.”

The idea of meddling with the DNA of wild animals to save them does not sit well with everyone. Scientists, ethicists, and environmentalists have raised objections to the idea of unleashing gene-edited creatures — including those that used to be extinct — without fully understanding the potential consequences. Cam Walker, a spokesman for Friends of the Earth Australia, says gene editing introduces new risks to ecosystems when people should be focused on preserving the natural world.

“We do not support gene editing in conservation,” he said. “The entire process involves many random events whose end results cannot be predicted.”