Scientists clone extinct frog that births young from its mouth

Rhett A. Butler, mongabay.com
March 18, 2013

Australian scientists have produced cloned embryos of an extinct species of frog known for its strange reproductive behavior, reports the University of New South Wales.

The amphibian, the gastric-brooding frog (Rheobatrachus silus), one of only two species that swallowed its eggs, brooded the young in its stomach, and gave birth through its mouth. But it went extinct in 1983. The closely-related R. vitellinus died out in the wild in in 1985.

However a team of researchers were able to recover cell nuclei from frozen frog tissue collected in the 1970s and implant it into a fresh egg from another frog species, Mixophyes fasciolatus. Some of the eggs then developed into an early embryo stage, although none survived longer than a few days.

The scientists said the process — which has not yet been published — could eventually lead to the resurrection of the extinct species.

An artist’s impression of the gastric-brooding frog. Artwork: Peter Schouten
"We are watching Lazarus arise from the dead, step by exciting step," said University of New South Wales Professor Mike Archer, leader of the aptly-named Lazarus Project. "We’ve reactivated dead cells into living ones and revived the extinct frog’s genome in the process. Now we have fresh cryo-preserved cells of the extinct frog to use in future cloning experiments."

"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."

The work may have implications beyond bringing back to life a biological curiosity. Scientists have been interested in the gastric-brooding frog's ability to shut down the secretion of digestive acids and the implications for developing treatments for gastric ulcers.

Archer announced the progress on March 15 at the TEDx DeExtinction event in Washington DC, which assembled researchers from around the world who are working to resurrect other extinct plants and animals, including the woolly mammoth, dodo, Cuban red macaw and New Zealand’s giant moa.

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Rhett A. Butler, mongabay.com (March 18, 2013).

Scientists clone extinct frog that births young from its mouth.