Scientists produce cloned embryos of extinct frog

Jul 7, 2014

By Science Daily

The genome of an extinct Australian frog has been revived and reactivated by a team of scientists using sophisticated cloning technology to implant a “dead” cell nucleus into a fresh egg from another frog species.

The bizarre gastric-brooding frog, Rheobatrachus silus — which uniquely swallowed its eggs, brooded its young in its stomach and gave birth through its mouth — became extinct in 1983.

But the Lazarus Project team has been able to recover cell nuclei from tissues collected in the 1970s and kept for 40 years in a conventional deep freezer. The “de-extinction” project aims to bring the frog back to life.

In repeated experiments over five years, the researchers used a laboratory technique known as somatic cell nuclear transfer. They took fresh donor eggs from the distantly related Great Barred Frog,Mixophyes fasciolatus, inactivated the egg nuclei and replaced them with dead nuclei from the extinct frog. Some of the eggs spontaneously began to divide and grow to early embryo stage — a tiny ball of many living cells.

Although none of the embryos survived beyond a few days, genetic tests confirmed that the dividing cells contain the genetic material from the extinct frog.

The results are yet to be published.

“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, in 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.

12 comments on “Scientists produce cloned embryos of extinct frog

  • My only concern about bringing back extinct species is the question of whether their unique environmental niche still exists. When something goes extinct the niche that the creature occupied is often quickly filled by something else. So if there is no place for them in the present world, then I say leave them be.



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  • Booska

    When something goes extinct the niche that the creature occupied is often quickly filled by something else. So if there is no place for them in the present world, then I say leave them be.

    In the case of many frog species, the extinctions are caused by alien diseases, imported into their habitats from abroad, by human transport systems.



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  • de-extinct woolly mammoth, dodo, giant moa

    To echo the oft mentioned question: how to make the general public aware of our smaller kin? Favoring “cute, cuddly, adorable” animals is understandable, count me in. However, let us stop saying “well, it’s just a [ ]”. ET inter-office memo – humans? it’s just a [ ].

    Consider the burying beetle, reintroduced to a prairie reserve, or a rare fungus, that rightly aborted a strip mall development. The maples need sun also.



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  • It’s possible the ecosystems of the globe have been out of balance since the megafaunal extinctions over ten thousand years ago. If you look at the fossil species from the Cenozoic and Mesozoic periods (and, to a degree, the late Palaeozoic too), there were hundreds of gigantic species during any particular geological epoch, from the giant fish and amphibians of the Devonian and Carboniferous periods to the huge mammals, reptiles, and birds of the Pleistocene. Today, we have about five species that fit into that size range on land: the two elephant species, the two rhino species, and one hippopotamus species. This doesn’t necessarily answer the point about microfauna (those things usually have fast generation rates and consequently evolve faster), but it offers a glimmer of promise for projects like this one.



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  • i like too read stuff like deextinction.. i hope im still alive when they make that breakthrough.. if they make it happen its like that neil armstrong land on moon. a great news for human acheivements… so sorry for those creationist. i hope they bring the neanderthal back.. coz they have its dna.



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