Gastric brood frogs stand out for their peculiar reproduction habits. After the usual external fertilization process, most frogs abandon their progeny. But, in a fascinating departure from the norm, the female gastric brood frog ingests about forty fertilized eggs and the young tadpoles hatch and develop in the mother's stomach. During the incubation, the mother doesn't eat, although apparently she does digest some of the embryos. When the incubation is sufficiently advanced, her lungs collapse and the mother and relies on gas exchange through the skin. After about six weeks there is a "re-birth," well, regurgitation really, of about 20 to 25 fully-developed froglets. This behavior reminds me a little bit of Darwin's frog, in which the young incubate in the vocal sacs of the male, or Egyptian mouthbreeders, in which the eggs and young are protected and reared in the mouth of the mother.
Sadly, both species of gastric brooding frogs, which resided in Eastern Australia, became extinct in the mid-1980s. What a shame. A loss of an interesting critter.
But is there hope for the species yet? Recently, a research group led by Mike Archer of the University of New South Wales in Sydney in Australia has reported the transfer of frozen gastric brooding frog DNA genomes into donor eggs derived from the Great Barred Frog in which the donor DNA had been inactivated. The result of the so-called "Lazarus Project," was the creation of a small mass of embryonic cells containing gastric brooding frog DNA. None of the embryos survived beyond a few divisions.
One matter of clarification, even if the embryos had developed into adults, it would be a bit of a stretch to call this even an abortive "rescue" of the species. There are profound epigenetic events that are mediated by the maternal RNA, i.e. the RNA in the donor oocyte, which have been documented in several organisms, including frogs. It would be more accurate to say that experiment resulted in a "rescue" or resuscitation of the nuclear genome of the gastric brooding frog. Nevertheless, the research team is optimistic that using refinements of the technology they will soon be available to clone and raise adult frogs. Similar experiments were performed in the creation of Dolly, the sheep, the first vertebrate cloned from an adult cell, although the donor oocytes were derived from the same species.
This is of broad academic interest, since there are similar experiments underway or contemplated to clone a number of extinct species, such as the passenger pigeon, the great auk, and even wooly mammoths (using modern elephants as egg donors).
What does this all mean? Recently, a TED-X conference sponsored by National Geographic, was convened to discuss the ethical and practical issues related to "De-Extinction." Although, videos of the conference have yet to be released, it will be interesting viewing.
Where do I come down on this issue? I really don't know, but I offer the following: 1)I don't believe that any of these creatures should be released into the wild. Repopulating North America with semi-pseudo wooly mammoths or frankenfrogs? Bad idea. 2)I really wonder what conclusions can be drawn from the possible results of these experiments? Can we ever draw definitive conclusions about the behavior and biology of these "resurrected genomes?" Even the Dolly experiments, using donor eggs from the same species, resulted in adult animals with serious health problems and I expect that using donor eggs from differing species will result in even greater deviations from normal adults.
Although the expansion of humanity has had cataclysmic consequences on both the ecology of the planet and the destruction of species diversity, it is believed that 99% of the known organisms that ever lived have become extinct. Most of these extinctions preceded human beings. Extinction is not exceptional; it is the norm in planetary history.
Personally, I wonder if we would be better served by rescuing charismatic animals (like tigers and blue whales), and studying ways to try and prevent the extinction of surviving species, primarily by protecting and preserving habitats and ecosystems, rather than trying to resurrect lost organisms. This would seem to me to be a more efficient and valuable use of scarce scientific resources. Agree or disagree, that's my take. Rebuttal is always welcome.
Sadly, both species of gastric brooding frogs, which resided in Eastern Australia, became extinct in the mid-1980s. What a shame. A loss of an interesting critter.
But is there hope for the species yet? Recently, a research group led by Mike Archer of the University of New South Wales in Sydney in Australia has reported the transfer of frozen gastric brooding frog DNA genomes into donor eggs derived from the Great Barred Frog in which the donor DNA had been inactivated. The result of the so-called "Lazarus Project," was the creation of a small mass of embryonic cells containing gastric brooding frog DNA. None of the embryos survived beyond a few divisions.
One matter of clarification, even if the embryos had developed into adults, it would be a bit of a stretch to call this even an abortive "rescue" of the species. There are profound epigenetic events that are mediated by the maternal RNA, i.e. the RNA in the donor oocyte, which have been documented in several organisms, including frogs. It would be more accurate to say that experiment resulted in a "rescue" or resuscitation of the nuclear genome of the gastric brooding frog. Nevertheless, the research team is optimistic that using refinements of the technology they will soon be available to clone and raise adult frogs. Similar experiments were performed in the creation of Dolly, the sheep, the first vertebrate cloned from an adult cell, although the donor oocytes were derived from the same species.
This is of broad academic interest, since there are similar experiments underway or contemplated to clone a number of extinct species, such as the passenger pigeon, the great auk, and even wooly mammoths (using modern elephants as egg donors).
What does this all mean? Recently, a TED-X conference sponsored by National Geographic, was convened to discuss the ethical and practical issues related to "De-Extinction." Although, videos of the conference have yet to be released, it will be interesting viewing.
Where do I come down on this issue? I really don't know, but I offer the following: 1)I don't believe that any of these creatures should be released into the wild. Repopulating North America with semi-pseudo wooly mammoths or frankenfrogs? Bad idea. 2)I really wonder what conclusions can be drawn from the possible results of these experiments? Can we ever draw definitive conclusions about the behavior and biology of these "resurrected genomes?" Even the Dolly experiments, using donor eggs from the same species, resulted in adult animals with serious health problems and I expect that using donor eggs from differing species will result in even greater deviations from normal adults.
Although the expansion of humanity has had cataclysmic consequences on both the ecology of the planet and the destruction of species diversity, it is believed that 99% of the known organisms that ever lived have become extinct. Most of these extinctions preceded human beings. Extinction is not exceptional; it is the norm in planetary history.
Personally, I wonder if we would be better served by rescuing charismatic animals (like tigers and blue whales), and studying ways to try and prevent the extinction of surviving species, primarily by protecting and preserving habitats and ecosystems, rather than trying to resurrect lost organisms. This would seem to me to be a more efficient and valuable use of scarce scientific resources. Agree or disagree, that's my take. Rebuttal is always welcome.
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