http://phenomena.nationalgeographic.com ... or-a-womb/
Resurrecting the Extinct Frog with a Stomach for a Womb
by Ed Yong
Two years ago, Mike Archer from the University of New South Wales looked down a microscope and saw that a single fertilised frog egg had divided in two. Then, it did it again. And again. Eventually, the egg produced an embryo containing hundreds of cells.
“There were a lot of hi-fives going around the laboratory,” says Archer.
This might seem like an over-reaction. After all, millions of frog eggs divide into embryos every day, as they have done since before dinosaurs walked the earth. But this egg was special. Archer’s team of scientists had loaded it with the DNA of the southern gastric brooding frog—a bizarre creature that has been extinct for almost 30 years.
The fact that it started to grow into an embryo was a big deal. The fact that it never went further was disappointing, but not unexpected. This is cutting-edge science—cloning techniques put to the purpose of resurrection.
Archer’s goal is simple: To bring the extinct gastric brooding frog back from oblivion and, in doing so, provide hope for the hundreds of other frogs that are heading that way. Getting the embryo was a milestone and Archer is buoyantly optimistic that he’ll cross the finish line soon. Lazarus, he says, will rise again.
And background on the frog:
Simply put, the mother frog converts her stomachs into a womb. She swallows her own eggs and stops making hydrochloric acid in her stomach to avoid digesting her own young. Around 20 to 25 tadpoles hatch inside her and the mucus from their gills continues to keep the acid at bay. While the tadpoles grow over the next six weeks, mum never eats. Her stomach bloats so much that her lungs collapse, forcing her to breathe through her skin. Eventually, she gives birth to her brood through “propulsive vomiting”, spewing them into the world as fully-formed froglets.