UNSW - Science

Research: Bid to revive extinct gastric-brooding frog

Saturday, 16 March, 2013
A gastric-brooding frog in its natural habitat. Artwork: Peter Schouten

An Australian team led by UNSW's Professor Mike Archer has succeeded in growing early stage cloned embryos containing the DNA of an extinct frog.

The research is the first vital step in Project Lazarus, a “de-extinction” project aimed at bringing the Australian gastric-brooding frog back to life.

The bizarre frog, Rheobatrachus silus – which uniquely swallowed its eggs, brooded its young in its stomach and gave birth through its mouth - became extinct in 1983.

The team has been able to recover cell nuclei from tissues collected in the 1970s and kept for 40 years in a conventional deep freezer.

In repeated experiments over five years, the researchers used a laboratory technique known as somatic cell nuclear transfer. They took fresh donor eggs from the distantly related Great Barred Frog, Mixophyes fasciolatus, inactivated the egg nuclei and replaced them with the dead nuclei from the extinct frog. Some of the eggs spontaneously began to divide and grow to early embryo stage – a tiny ball of many living cells.

Although none of the embryos survived beyond a few days, genetic tests confirmed that the dividing cells contain the genetic material from the extinct frog.

The results are yet to be published.

“We are watching Lazarus arise from the dead, step by exciting step,” says Professor Archer, of the School of Biological, Earth and Environmental Sciences. “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 technical work was led by Dr Andrew French and Dr Jitong Guo, formerly of Monash University, in a University of Newcastle laboratory led by frog expert, Professor Michael Mahony, along with Mr Simon Clulow and Dr John Clulow.  The frozen specimens were preserved and provided by Professor Mike Tyler, of the University of Adelaide, who extensively studied both species of gastric-brooding frog – R. silus and R. vitellinus - before they vanished in the wild in 1979 and 1985 respectively.

Professor Archer spoke publicly for the first time today about the Lazarus Project and also about his ongoing interest in cloning the extinct Australian thylacine, or Tasmanian tiger, at the TEDx DeExtinction event in Washington DC, hosted by Revive and Restore and the National Geographic Society, on March 15.

Researchers from around the world had gathered there to discuss progress and plans to ‘de-extinct’ other extinct animals and plants. Possible candidate species include the woolly mammoth, dodo, Cuban red macaw and New Zealand’s giant moa.

Professor Archer's TEDx address can be seen here.. You will need to scroll down the list of speakers to Second Chance for Tasmanian Tigers and Fantastic Frogs.

Lazarus project media contacts: m.archer@unsw.edu.au; 9385 3446

UNSW Science media contact:  Deborah Smith, 9385 7307, 0478 492 060, Deborah.Smith@unsw.edu.au;

Andrew French: afrench4@optusnet.com.au, Michael Mahony: Michael.mahony@newcastle.edu.au, 02 4921 6014; Simon Clulow, simon.clulow@newcastle.edu.au.

Funding:  The Lazarus Project has been funded through the generosity of donors - particularly Professor John Shine, Mr Dick Smith, Mr Gary Johnston - and by the researchers themselves.