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Scientists clone extinct frog that gives birth from its mouth


March 17, 2013

An artist’s impression of the gastric-brooding frog that was cloned by scientists working on the Lazarus Project (Artwork: Peter Schouten)

An artist’s impression of the gastric-brooding frog that was cloned by scientists working on the Lazarus Project (Artwork: Peter Schouten)

Australian scientists have successfully revived and reactivated the genome of an extinct frog. The "Lazarus Project" team implanted cell nuclei from tissues collected in the 1970s and kept in a conventional deep freezer for 40 years into donor eggs from a distantly-related frog. Some of the eggs spontaneously began to divide and grow to early embryo stage with tests confirming the dividing cells contained genetic material from the extinct frog.

The extinct frog in question is the Rheobatrachus silus, one of only two species of gastric-brooding frogs, or Platypus frogs, native to Queensland, Australia. Both species became extinct in the mid-1980s and were unique amongst frog species for the way in which they incubated their offspring. After the eggs were fertilized by the male, the female would then swallow the eggs until they hatched. The tadpoles would then develop in the female’s stomach for at least six weeks – during which time the female would not eat – before being regurgitated and raised in shallow water.

With the aim of bringing the frog back from extinction, the Lazarus Project team took fresh donor eggs from the Great Barred Frog, another Australian ground-swelling frog that is distantly related to the gastric-brooding frog. The scientists inactivated the egg nuclei from the donor eggs and replaced them with dead nuclei from the extinct frog in a technique known as somatic-cell nuclear transfer (SCNT), which was the basis for the cloning of Dolly the sheep and, more recently, 581 clones from one “donor” mouse.

Although none of the embryos survived longer than a few days, the work is encouraging for others looking to clone a variety of currently-extinct animals, such as the woolly mammoth, dodo, Cuban red macaw and New Zealand’s giant moa.

“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, Sydney. “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.”

Professor Archer spoke last week at the TEDx DeExtinction event in Washington, D.C., where he talked publicly about the Lazarus Project for the first time, as well as his ongoing interest in cloning the extinct Tasmanian tiger.

The Lazarus Project team's results are yet to be published.

Source: University of New South Wales

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

"Survival of the fittest" will be consigned to history.


If this is being done in the scientific community in the name of "bettering" the human race...ladies you may have a difficult choice to make sometime in the future. ಠ_ಠ

Trystan Knight

If the eggs were hatched in the stomach, it would seem that chemistry or its lack would affect the successful development of the embryos. What's in a frog's stomach? If it's anything like ours, it's an acid so strong it can burn holes in paper. Very interesting!

Molly Cruz

@Australian: "Survival of the fittest" has already been consigned to history. It began its phase out with the beginning of the industial revoultion. When humans began radically altering their environment we changed the rules, and survival of the fittest was one of the first we changed out of greed and/or "compassion."


The Svalbard Global Seed Vault is for flora and we certainly need one for fauna. I hope that they are successful in bringing these frogs back from extinction. It's just too bad that we have to ruin habitat for personal gain. Man is a pestilence and scourge upon this green earth.


Wow, here and I thought people were natural. Thus our actions were natural. Guess not. I think it's time for those that see people as pestilence to lead the way. I'm sure that'll happen right after Al Gore drives a golf cart, lives in a recycled container and flies economy.

Jeff Vandervort

Does Anyone else here know what happened in Jurassic Park? Just Sayin'...


Buell rider if man is derived from nature then what is happening is natural, if not perhaps you should sell your Buell and walk?

Heather Bowman

Hmm... if this was applied to the human race, then we might be calling men "Daddy Seahorses"

Azar Attura

Jurassic Park here we come..


To reinstate extinct creatures into existence again surely is possible now however creating biological specimens with never before features is out of the question. That level of bioengineering is only done by God.

Bryce Guenther

Why not crank up some good old fashion evolution and start the process over? Write your own DNA. After all it was just an accident! Surely with the great knowledge available and perfect labs it would be no problem to start up the old evolver! It sounds easy - just get all the ingredients - mix them up and out comes a frog!


@VirtualGathis it is still survival of the fittest, just the fittest for the given situation or niche. We happen now to define that niche but those which survive are those which are best suited for the given environment. This is true even if we are making choices about breeding animals. Then we have a much closer hand in what we define as fit.

Jonathan Shock


Suzanne Gale

Surely with such a doting mom, you would expect them not to go extinct.

"... however creating biological specimens with never before features is out of the question"

Yes, we do. Monkeys aren't supposed to be luminescent under UV-light and yet they are created and glow green, or orange, or whatever color you will. Mutating a new feature in an organism isn't hard either, but most of the times it's harmful or useless to the organism like most mutations in nature are.

Nature runs her course with no help of a mythical figure.

Fretting Freddy the Ferret pressing the Fret
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