Health & Science
3:20 pm
Fri March 29, 2013

De-Extinction: Just Around The Corner?

Carl Zimmer talks to Going Public host Jacob McCleland.

We may soon have to reclassify extinction, according to a new report in National Geographic Magazine. Some species may only be “bodily extinct,” but not genetically, because scientists are closing in on the technology to clone species that no longer roam the earth.


But forget about dinosaurs or some Michael Crichton-inspired world where long-dead beasts terrorize an island paradise. At present, the most likely candidates for de-extinction are those that died within the past few tens of thousands of years. Think about animals that have died in our recent past, like the passenger pigeon, gastric brooding frog or even the wooly mammoth. 

Carl Zimmer is a an award-winning science writer who wrote the article for National Geographic. He also writes for Wired and regularly contributes to the New York Times. Zimmer told KRCU’s Going Public that scientists are quite close.

“If there’s a species that goes extinct and scientists have already saved some of its cells and then frozen them away, that’s a really promising possibility,” Zimmer said.

The gastric brooding frog may become the first extinct animal to be successfully cloned. This Australian frog went extinct in 1980, only a few years after researchers discovered it. The female gastric brooding frog had the unique ability to rear young in her stomach. After the male frog fertilized the eggs, the female would stop making stomach acid and she would swallow the eggs. The eggs would hatch in her stomach, where the young frogs would develop until she “puked them up,” Zimmer said.

Zimmer said this amazing adaption led some scientists to decide that if there is a species to bring back, this is it. 

“Scientists have been able to produce embryos where there are these frog cells that are dividing and developing,” Zimmer said. “They haven’t gotten to the point where they’re making adult frogs yet, but they’re almost there.”

It  might be possible to collect DNA fragments from fossils and then engineer complete DNA to produce extinct species, like the wooly mammoth. 

The passenger pigeon is another option. Billions of passenger pigeons once flew through the skies of the eastern United States and Canada until hunting decimated their numbers. The last passenger pigeon died in 1914. Several dead passenger pigeons are still in museums, and though Zimmer said there are no live cells in these birds, scientists can pull out bits to DNA to reconstruct their whole genome. Scientists are still at the beginning of a this project, with the help of a non-profit organization called Revive and Restore.

“What they would like to do is take the DNA of a living pigeon and put in little chunks of DNA to correspond to what they find in the passenger pigeon,” Zimmer said. “Then they would have to do some pretty fancy cloning to produce new birds that would be passenger pigeons.”

Nobody has ever cloned a bird before.

Zimmer believes cloning technology does not take away from the urgency to protected endangered species like the polar bear. It’s much easier to protect animals in the wild than to rebuild the species through technology. “We have yet to produce a single healthy individual through de-extinction,” Zimmer said. Cloning is just another tool in the toolbox that conservationist can use to preserve species. 

“A single individual is not a species. It’s not a group of animals that’s going to be able to just take care of itself for the foreseeable future. It’s a huge undertaking. Nobody who is looking into de-extinction is saying we don’t have to conserve species,” Zimmer said.

There are a lot of species that are now functionally extinct, Zimmer said, like the northern white rhinoceros. He said there are only four individuals left, and researchers have not had any success in breeding them.

“When those animals die, does that mean we’re done? We can’t try any further? Or is there a possibility that we can keep working to try to bring them back and to restore those environments,” Zimmer said.