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Back From the Dead?
Photograph from ANT Photo Library/Science Source
In this file photo, a tiny froglet can be seen in the mouth of its mother, the southern gastric-brooding frog Rheobatrachus silus. (Related: "Resurrecting the Extinct Frog with a Stomach for a Womb.")
In this novel form of parental care, the female swallowed her fertilized eggs. Her stomach then stopped producing acid, becoming a makeshift womb. Later, she regurgitated fully formed froglets. (Watch a video of a frog father spitting out his young.)
Two species of gastric-brooding frogs made their homes in creeks in a relatively small area of tropical forest in Queensland, Australia: R. silus and the northern gastric-brooding frog, R.vitellinus.
The species were discovered in 1973 and 1984, respectively, but by the mid-1980s they had both disappeared, possibly due to habitat degradation, pollution, and disease, including chytrid fungus.
A few specimens of gastric-brooding frogs are preserved in Australian museums, leading scientists to ponder whether the animals could be reborn. (Related pictures: "Extinct Species That Could Be Brought Back.")
Now, scientists with the Lazarus Project have started to revive R. silus using cloning technology—the first attempt to revive any vanished species and a play to "get over this idea that extinction is forever," project leader Mike Archer told National Geographic.
Archer was speaking at Friday's TEDx Conference on DeExtinction at National Geographic headquarters in Washington, D.C.
As part of the project, Archer and colleagues have implanted a "dead" cell nucleus from a frozen gastric-brooding frog into a fresh egg from a distantly related frog species, the great barred frog.
During five years of experiments, the team has been able to get some of the eggs to spontaneously divide and grow into early embryos. (Related: "How to Resurrect Lost Species.")
Although none of the embryos survived more than a few days, genetic tests confirmed that the dividing cells contain genetic material from the extinct frog, according to the team.
Archer, of the University of New South Wales in Sydney, isn't sure why they can't get past the embryo stage, but he suspects it may have to do with how the scientists are handling the eggs-a process that his team is working on right now.
"We're all very optimistic that we're going to get this frog hopping glad to be back in the world."
—Brian Howard and Christine Dell'Amore
Published March 16, 2013
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Egg Donor
Photograph courtesy Bob Beale
The Project Lazarus team has implanted nuclei from preserved gastric-brooding frogs into the great barred frog (pictured).
Archer decided to revive R. silus because a lot of the early cloning research has been done on frogs, he said. He also picked the species because much is still unknown about gastric-brooding frogs' extremely unusual biology—the amphibians went extinct not long after they were discovered. (Should we bring back extinct species?)
Understanding how an animal can stop its stomach from producing gastric juices, for instance, could have useful applications for people with digestive problems.
Ben Novak, a research and science consultant at Revive & Restore and a speaker at the TEDx conference, added that he thinks it's possible to bring gastric-brooding frogs back.
"Museum-tissue DNA can be rather low quality," Novak cautioned.
But, he said, new gene-sequencing technology that has become available in the past three years has made it possible to start getting better results. (Get a genetics overview.)
"Any taxidermied or museum-preserved tissue can yield a whole genome with a piece of tissue the size of a pin head," said Novak.
Published March 16, 2013
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Frozen Frog
Photograph courtesy Bob Beale
This "remarkably well-preserved" gastric-brooding frog, frozen since 1980, was used by the Project Lazarus team in their first attempt to clone R. silus. (Related pictures: "Ten Most Wanted 'Extinct' Amphibians.")
If the team brings back the gastric-brooding frog, that's only the beginning—scientists will have to selectively breed the frogs to become resistant to the chytrid fungus, a likely culprit behind their demise, Archer said.
Published March 16, 2013
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Cough it Up
Illustration by Peter Schouten/Lazarus Project
In an illustration, R. silus coughs up its babies in a mountain rain forest in eastern Queensland, Australia.
In most frog species, the egg hatches into a tadpole, which then feeds on plant material until it becomes an adult frog. Not so in gastric-brooding frogs—tadpoles mature in their mother's stomach, until she becomes so swollen with babies she's forced to throw them up.
Swallowing fertilized eggs is actually clever, Archer noted, since the frog is protecting the eggs from predators in its stomach.
Overall, once this unique species is revived, "everyone can get more vigorously excited about trying [to resurrect] more extinct species," he said. "I hope it's a flagship of success."
Published March 16, 2013
6 comments
i had a fish that did this too, from Africa. in the store they where called yellow lab, and are from Lake malavy.
3 Like
In all honesty, I would rather see resources being put towards preventing further extinctions. Even if we are able to clone this species, unless the problems that caused the extinction in the first place have been corrected, re-introduction into the wild will fail.
Furthermore, I fear that the ability to bring extinct species back may actually hinder conservation efforts, there will be less concern about preserving existing ecosystems if we can bring them back once extinct.
Finally, I don't see how we would be able to bring them back with enough genetic diversity to persist on their own. And the mtDNA would be radically different, would they really be the same species?
@Alice Wonder While this particular species seems to have value in terms of medical research, the prevention of further extinctions among wildlife and habitats that are currently endangered is actually a reason we should consider bring back some extinct species. Some animals that have gone extinct due to human involvement were keystone species in their environments. They played very important roles that supported a plethora of other organisms that actually suffered greatly from the loss of such species. Bringing back such extinct animals can act as a tool to help us preserve other animals and habitats.
Addressing the reasons that they went extinct is also very important. Some animals died out because of habitat loss. It's unlikely that those species could be successfully reintroduced unless their habitats are restored. But other species, such as the Cuban Makaw which went extinct due to over hunting for the pet trade, still have habitats that they can be returned to.
I am amazed by the variety of life and the versatility of its abilities to survive. In this case human intervention was needed. Thank you, good humans, who cared enough to say that this is life unique and all life is precious. Bless You, C N Cisco
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