Cloning brings extinct frog back from dead

By Mischa Vickas March 19, 2013
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Frozen tissue has allowed the bizarre gastric brooding frog – which gives birth via its mouth – to rise from the dead.

IT’S NOT EXACTLY Jurassic Park – not yet anyway – but Australian researchers have briefly revived an extinct species using frozen tissue and cloning technology to produce a live embryo.

“We are watching Lazarus arise from the dead, step by exciting step,” says Professor Mike Archer, a palaeobiologist at the University of New South Wales in Sydney, who led the project. 

After the accidental discovery of frozen frog tissue several years ago his team were able to attempt cloning to bring the lost species back, says Mike. Though the embryos did not survive to adulthood, this represents the first time an extinct species has been revived.

Bringing extinct animals back from the dead

“The implications for other extinct and declining species are huge,” says Dr Simon Clulow, a biologist at the University of Newcastle who took part in the research. He says the feat opens up avenues for reviving other lost creatures, such as the Tasmanian tiger.

Queensland’s southern gastric-brooding frog, was one of two related species that swallowed its eggs and incubated tadpoles in its stomach, before giving birth to fully formed froglets via its mouth. Along with the northern gastric brooding frog it went extinct in the mid 1980s. 

For the project, the experts inserted a dead cell nucleus of the southern gastric-brooding frog (Rheobatrachus silus) into the living donor egg of a related species, the great barred frog. The researchers first ensured that all existing genetic material was removed from the donor egg.

Frog gives birth through its mouth

The researchers managed to produce embryos – clumps of cells that survived for a few days.

“We’re increasingly confident that the hurdles ahead are technological and not biological and that we will succeed,” says Mike. “Importantly, we’ve demonstrated already the great promise this technology has as a conservation tool when hundreds of the world’s amphibian species are in catastrophic decline.”

The reason why the researchers chose the gastric-brooding frog, discovered near Brisbane in 1973, was because of its “unique and amazing evolution,” says Simon, who is an Australian Geographic Society sponsored researcher.

“The gastric-brooding frog evolved some of the most incredible strategies for reproductive success that have ever been observed in Australia, or indeed the world,” he says. 

The reversal of extinction?

Simon argues that the research highlights the need for Australia to develop a bank of genetic material so that if the technology proves itself, future species extinctions can be avoided.

Half of all amphibians are in decline and 30 per cent are faced with extinction, largely as a result of human activity, says Simon.

The results of the project were presented in the US on Friday at TED conference for researchers discussing the possibility of bringing other extinct species back, including the woolly mammoth, the moa and the dodo.

Over the last decade other projects have looked at sequencing the genome of the Tasmanian tiger, and even reviving it using tissue from museum specimens, but they have been scuppered by technical or financial hurdles.