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IVF, surrogacy to save frogs?

Tusked frog

Tusked frog (Adelotus sp.), listed as vulnerable, could be saved as a species with IVF, if scientists are successful.

Credit: Ian Morris. Amazing Facts About Australian Frogs and Toads and A Wild Australia Guide Frogs, Steve Parish Publishing.

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Challenges ahead

Because most frogs lay eggs that are fertilised externally by male frogs, the IVF process is much less complex than it is for humans - the sperm and eggs need only be mixed in a petri dish with water.

However, the scientists still have their work cut out for them. "To date, it has been impossible to freeze frog eggs successfully," Lloyd said.

Frog eggs are 10 times the size of a mammalian egg, so they are too big to penetrated by the chemicals that protect them from being destroyed in the freezing process.

Frog sperm, on the other hand, freezes well so researchers in Germany are experimenting with ways to use two sperm cells and an egg from a non-threatened species to make offspring.

Still more challenging is IVF for the few frog species that brood their eggs internally. It may be possible to use surrogate mothers from more common species, but very little is known about the reproductive anatomy and physiology of most amphibians, so this approach could be tricky, Lloyd said.

The biobank follows in the footsteps of the 'doomsday' seed vault in Norway and Frozen Ark in the UK, which preserves DNA and, where possible, sperm and eggs from a wide variety of endangered species.

Amphibian Ark hopes to establish a global network of biobanks just for amphibians - important work, Czechura said. "Once, where you had seven or eight species calling along creeklines, now there's dead silence," he said. "It's a tragedy."

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