Scientists briefly revive extinct frog from dead cells

Australian scientists break new ground in embryonic cloning by bringing back a dead frog species using eggs from a distant cousin.

Rheobatrachus silus frog
Rheobatrachus silus frog with a baby in its mouth. D. Sarille

The Rheobatrachus silus frog has been extinct since 1983. This unusual Australian creature was known for swallowing its eggs and then releasing the young from its mouth. That's way too awesome to just let the animal be resigned to the biological history books.

Australian researchers have spent five years conducting experiments using somatic-cell nuclear transfer, a technique for creating a cloned embryo. Appropriately enough, it's called the Lazarus Project. The scientists took donor eggs from a related frog and replaced the nuclei with dead nuclei from the extinct frog. Some of the eggs then began to grow.

I would love to say the results were a brood of happy, hopping baby frogs, but it didn't quite get that far. The embryos didn't make it past a few days, but they did give the researchers a fresh cache of living cells for future cloning experiments.

"We are watching Lazarus arise from the dead, step by exciting step," says the leader of the Lazarus Project team, Professor Mike Archer of the University of New South Wales in Sydney. Researchers from the University of Newcastle are also participating in the project.

The results are remarkable, especially considering the extinct frog's cell nuclei was gathered from tissues collected in the 1970s and kept in a deep freeze for the last four decades.

The initial success of the Lazarus Project gives scientists a considerable amount of hope. "We're increasingly confident that the hurdles ahead are technological and not biological and that we will succeed. 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," Archer says.

 

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