TEDxDeExtinction 3/15/13 Meeting Report
by David Biello (blogger for Scientific American)
The public debut of the de-extinction idea took place at the Washington, D.C. headquarters of the National Geographic Society. The murmur of excitement typical of any TED event rippled through the crowd, with perhaps more hope than angst detectable in the susurration, as a soundtrack chosen by Brian Eno washed over the attendees. A series of pictures of endangered animals from wildlife photographer Joel Sartore—the eastern indigo snake, an ocelot, the woodland caribou, even a freshwater mussel—flashed across the big screen behind the stage, followed by a woolly mammoth warning the audience to turn off cellphones.
Ryan Phelan and Stewart Brand served as masters of ceremonies, Brand intoning, “This is a weird day. The first public discussion of something brewing for a year or two: the possibility of bringing back extinct species, for real.” The day-long event aimed at discussion of where this idea of de-extinction is currently at in terms of development, where it is headed (and how fast), what it might mean, and ultimately how to think about this new potential. The day was subdivided into a five part program of the Introduction, the Who, the How, the Why and Why Not, and the hope of Wild Again.
A brief introduction by National Geographic’s John Fahey followed. He noted that the Society is now some 125 years old and founded on the principle of quenching curiosity through exploration. Now, as part of a new century of exploration, the time has come to explore this idea of de-extinction — the kind idea worth spreading espoused by TED. And TED’s Chris Anderson spoke of the multiplier effect of this kind of TEDx event, how each could explore the frontiers of paradigm shifting ideas. Because it is a paradigm shift to think that the mostly unintended, unconscious extinctions caused by us and our ancestors could be reversed to bring back vanished plants and animals. That is a message of hope all too often missing from conservation. “All my life, the narrative of our relationship with nature has been one of this heroic, but losing battle,” Anderson said. “I’m sick of it,” and de-extinction is just one way for humanity to begin to play offense rather than defense in the face of the sixth mass extinction in the planet’s history.
To properly ground the day’s discussion, Brand brought on stage award-winning journalist Carl Zimmer. “This is a premonition of news,” Brand said. “We don’t have extinct species brought back to life yet–but it will be soon.”
Zimmer noted that he writes about the history of life for a living, and one of that profession’s occupational hazards is the constant wish for a time machine. Wouldn’t it be nice to go back in time to see all the weird creatures evolution has thrown up on the Earth’s stage, like the hairy alligator-like mammals that were the precursors to today’s whales? The movie “Jurassic Park” introduced us to the idea that we might not need a time machine, that we might be able to bring back extinct creatures through the shared language of DNA. Unfortunately the half-life of DNA precludes bringing back the dinosaurs—unless you count birds, which you really ought to—but it might enable us to bring back the mammoths who died out 3,700 years ago and were deep frozen in the Arctic tundra. Or perhaps we can pull the DNA from partially fossilized giant sloth dung and help that creature come back to save California’s remnant Joshua trees. It’s a simple matter of putting the chunks of DNA that matter to make a mammoth, paste those into its living relatives today and—what? This hybrid mammoth is neither a true mammoth nor quite an elephant, not to mention the fact that its ecosystem, the mammoth steppe of yesteryear, is entirely gone (though bringing back the mammoth might help bring back the ecosystem). The question becomes: should we do this if we can? “If we bring back species from the past, we have to think about bringing back their world as well,” Zimmer concluded, pegging as his favorite candidate for de-extinction the Steller’s sea cow eaten to death by hungry sailors in the 1700s. And that’s just one of the species we have eliminated.
As Ryan Phelan noted in introducing the next speaker, artist Isabella Kirkland has lovingly depicted 63 species have gone extinct since 1700. Her painting is, in a sense, a catalog of the candidates for de-extinction, shown life-size in archivally stable materials. “If the pictures are lucky, they might survive a century or more,” Kirkland said. Her painting that served as a cover image for the event is meant to keep this loss in people’s minds through time by capturing some of the uniqueness of each species, whether the great auk’s egg or the gastric breeding frog that gives birth by vomiting. “What we have left is remorse and remains,” Kirkland mused, as well as a certain knowledge of humanity’s hubris and our own vulnerability.
There is another abundant family even more vulnerable than us, however—birds. The majority of extinct species are birds, many of them from islands. Ornithologist Susan Haig nearly bounced off the stage in her excitement over the prospect of bringing some of them back. She advised never underestimating the enthusiasm—or the deep pockets—of bird enthusiasts. Such enthusiasm may even prove sufficient to counteract the potential cull by farmers who wiped out the Carolina parakeet in the 19th century because it raided their crops. But great care will have to be taken in the selection of bird species to bring back: “if you only have one or two and they fly away, you’re going to cry,” Haig warned. Good criteria might include: recent extinction, non-migratory to prevent that fly away problem, simple mating system, large clutch size, eggs not too big, and minimal parental care.
The woolly mammoth, as evolutionary molecular biologist Hendrik Poinar noted, was still living on islands in the Arctic when the Egyptians built the pyramids. The animals are well preserved in the frozen tundra, but probably not consistently enough for their DNA to remain intact and viable for cloning. But their fragmented “ancient DNA” has been recovered and reassembled. There is the challenge of the sheer size of the genome: “it’s mammoth” at 5 billion base pairs of the As, Cs, Ts and Gs that make up DNA, or nearly twice the size of the human genome. And once some version of the mammoth was back would it be exiled to Siberia and the Yukon only to disappear anew? “A part of the boy in me wants to see these majestic creatures walk across the permafrost,” Poinar admitted. “But the adult in me wonders whether we should.”
Paleontologist Michael Archer does not share that uncertainty. “If it’s clear that we exterminated these species, we not only have a moral obligation to see what we can do about it, but a moral imperative to do something if we can,” he said. His efforts focus on the thylacine—perhaps better known as the Tasmanian tiger or wolf—and the aforementioned gastric breeding frog, which turned its stomach into a uterus. For anthropocentric reasons we might want to bring this frog back so we could understand how it could so radically control its gastric secretions to manage that feat. And Archer announced that a team is on the way, having harvested cell nuclei from old freezer samples and coaxed them to divide. “It’s not a tadpole or a frog, but it’s a long way toward a frog,” he said. “I think we’re going to have this frog hopping glad to be back.”
Then there’s the thylacine, which might find a future as a marsupial canine companion for humans, though its habitat remains—as do people old enough to remember the last of these dog-like animals in the wild. There’s even a film of Benjamin, the last of the thylacines, to remind us of what we lost. That’s the kind of impact photographer Joel Sartore hopes to have as well, inspiring people to do something about the risk that we could lose too many species by the end of the century.
Spanish wildlife veterinarian Alberto Fernández-Arias detailed how his team has already achieved de-extinction—of the bucardo, a kind of Iberian ibex. The last female of this species was killed by a falling tree in 2000, but, fortunately, his team had cryogenically preserved its ear tissue a mere 10 months before this untimely death. Using those cells, and the techniques of somatic nuclear cell transfer—better known as cloning, like Dolly the sheep—they tried and tried again to get domestic goats to give birth to a bucardo. The key turned out to be hybridizing the goats with another kind of ibex and then implanting as many embryos as possible. Of 154 bucardo embryos transferred into 44 of these hybrid goats, only seven achieved pregnancy—and only one gave birth. But on July 30, 2003, the bucardo was de-extincted via C-section—for 10 minutes or so. The ibex quickly winked out of existence again thanks to a defect, a supplementary non-functional lobe that impaired her breathing. For the last 10 years, Fernandez-Arias lacked the funds to try anew but, at this meeting he secured a promise of funding, prompting a little jump and a “wow!” from host Stewart Brand.
As with the bucardo, having deep-frozen tissues of endangered species will be vital. In a sense, we should freeze it all and let our descendants sort it out. That’s exactly what Oliver Ryder of the Frozen Zoo aims to do, thus far having cyropreserved 503 mammals, 170 birds, 70 reptiles, 12 amphibians and fish—a small, and oddly weighted, subsection of extant biodiversity. Yet these cells, kept at a cool -197 degrees Celsius in high-tech camp coolers, remain the last best hope for species like the white rhinoceros that have “gene pools reduced to gene puddles,” as Ryder noted.
It is Robert Lanza’s avowed goal to use the techniques of cloning, or even better, cell reprogramming to restore the genetic variability of endangered species and increase the species abundance of the planet. Like Fernández-Arias he has already succeeded once—cloning the endangered Javan banteng. “It was surreal to see an exotic animal from the jungles of southeast Asia born in an Iowa field that reeked of cow manure,” he recalled of the April 2003 event. That banteng lived for seven years in the San Diego Zoo–an abbreviated life, but a life nonetheless. Stem cell reprogramming offers even more hope, given that it can take a skin cell from a man and turn it into an egg cell that could have come from a woman. “The technology is very powerful and developing very quickly,” Lanza noted, in what might prove a profound understatement.
At least, that’s the contention of synthetic biologist George Church, who noted that genomic technology is advancing faster than Moore’s Law, which allowed the kind of computing power confined to massive mainframes in the 1970s to fit in your pocket by the 2000s. In addition, DNA can now be precisely spliced into and out of a complete genome. Find the genes that make a mammoth different from an elephant–maybe sebaceous glands, hairiness, the hemoglobin to endure harsh winters, and the like–splice it in and, voila, a new kind of mammoth. “We can make a hybrid elephant with the best features of modern elephants and mammoths,” Church promised, an animal that might help combat climate change by restoring its own Arctic ecosystem.
It will not be as easy with all those extinct birds. “We don’t have the technology to bring extinct birds back to life,” argued developmental biologist Michael McGrew. A mammal’s egg is accessible to be adjusted when it is still a single cell, but you can’t do that with a bird egg. Roslin Institute has found a way to adjust whole gonads, however. For example, McGrew has put chicken cells into a duck that then mated with a hen and produced viable chicks. The technique might be use to restore the endangered bustard of the Middle East or revive the extinct passenger pigeon of North America.
That’s what graduate student Ben Novak is working on. As a teenager he did a science fair project to bring back the dodo—a kind of oversized, ground-based pigeon once native to the island of Mauritius. Its relative the passenger pigeon was once the most abundant bird in all of North America, a kind of biological storm that could black out the sky according to early observers. Yet by the turn of the 20th century all those birds were gone, victims of commercial hunting and loss of habitat. That habitat has, in the intervening years, grown back and given us our current profusion of white-tailed deer, turkeys and even bears, but not the pigeon. And while bringing it back via Lanza’s techniques may be a huge technical challenge, that monumental effort may pale in comparison to teaching any revived passenger pigeons how to be passenger pigeons. Novak’s idea is to dye homing pigeons to simulate passenger pigeon parents and lead the flocks from roost to roost until rehabituated to the old ways. “Eventually we will witness the passenger pigeon rediscovering itself in the forests of New England and the Great Lakes,” Novak hoped, and he has set to work at the University of California at Santa Cruz to make that hope a reality.
But if this hope ever becomes reality, it might have unintended consequences for conservation. After all, as resurrecting the woolly mammoth was discussed in DC, the world struggles to prevent elephants from being killed in Africa. Conservation biologist Stanley Temple worries that if extinction is no longer forever, that will diminish the perceived urgency for preventing species from becoming extinct in the first place. Plus, if reviving species moves forward it will require a kind of “resurrection biology” overview to ensure that the most appropriate species are brought back. “We should think carefully before the saber tooth cat is out of the bag,” Temple said. So, for example, the thylacine or ivory-billed woodpecker might make sense, as the conditions that drove them extinct are no longer a problem.
Regardless, preventing extinctions in the first place should remain a higher priority than bringing extinct species back—which may prove a distant prospect anyway. Novak’s passenger pigeon dreams do not address how the most social bird in history could possibly be recreated in any meaningful sense, noted biologist David Ehrenfeld. Nor is the DNA challenge so simple to solve, as the experience to date of genetic medicine in humans has shown. De-extinction is an expensive diversion from the hard and successful work of protected areas, population management, and public campaigns to reduce the consumption of endangered species–and it may have unexpected impacts on biodiversity itself, just as genetic engineering helped reduce the biodiversity of agricultural crops. “At this moment, brave conservationists are risking their lives to protect forest elephants from poachers,” he warned from his seat on stage. “And we’re talking in this safe auditorium about bringing back the woolly mammoth?”
Kate Jones described her initial reaction to the idea of de-extinction as “unmitigated horror” because of its potential as a diversion, a moral hazard, and yet another way for humans to create invasive species. But she quickly realized that if de-extinction becomes possible it will happen whether the conservation community likes it or not, and therefore conservation biologists should help guide the effort, for example helping decide which species are better or worse candidates for revival. Most importantly, a revived species would need to have extant habitat, like the islands of the North Atlantic just waiting for the great auk to come back. Those habitats would need to be free of threats, so there is no point in attempting to bring the “Goddess of the River” known as the baiji back to the Yangtze, which has only gotten worse since the dolphin’s extinction. And the passenger pigeon, despite Novak’s dreams, might be a bad idea since its complex social behaviors are no less extinct and its viable population size might be in the hundreds of thousands. Better candidates may be those species that provide some unique benefit or that are evolutionarily unique, like the thylacine.
Nor is the concept of de-extinction dreamt of by current legal philosophies, warned James Tate, who once served as the science advisor at the U.S. Department of the Interior. When asked what laws apply to the recovery of extinct organisms and their release into the wild, he said “very few.” That said, those that do apply, like perhaps the Endangered Species Act in the U.S., have a very broad reach. What kind of legal requirement descends on a scientist that brings back one organism from an extinct species? Our artificial constructs known as laws and regulations will have to adapt. “We run things right now, and nature does not,” he added.
Laws of man can be changed, but the laws of nature may prove less flexible. The half-life of DNA means it will be a much greater challenge to reconstruct the genome of the woolly mammoth, let alone recreate it, warned evolutionary molecular biologist Beth Shapiro. “Mammoth DNA is more like confetti that’s been run over by a herd of mammoth in the rain,” she noted, as she threw confetti out on the crowd. Completing a genome will be just the first step in a long road to de-extinction. Nor do we know the basics of why some species like the cave lion go extinct while their peers the caribou continue to thrive today, making it hard to prevent their re-extinction.
Nevertheless, there are several reasons we still might want to pursue the idea, bioethicist Hank Greely noted, such as scientific knowledge, technological progress, environmental justice and, most importantly perhaps, wonder. Balancing those hopes out on the hubris side are concerns like animal welfare–that first de-extincted bucardo certainly suffered. The passenger pigeon could end up being a vector for some terrible disease like bird flu, and people might rightfully question why geneticists gave them a pigeon rather than a cure for cancer. The ultimate societal objection may prove moral: this is simply something humanity should not do because these species went extinct for a reason that only God knows. On the other hand, “it would be awe inspiring to look at a woolly mammoth walking around, or a saber tooth, or a giant sloth,” Greely noted. “It would be cool.”
What also might be cool is recreating the wildlands of Europe and Asia. The cave paintings of our ancestors prove that the aurochs–a kind of giant cattle–were a key part of that ecosystem. And we might not even need the best of genetic technology to get them back, since simply cross breeding modern day cattle that still bear traces of their aurochs ancestry might allow us to revive them, said megafauna restoration specialist Henri Kerkdijk-Otten. He has already helped release bison into the Caucasus and auroch-tainted cattle into reserves in Spain. The Dutch even have a whole park devoted to this, a kind of African safariland in the lowlands of Europe, and the Russians have high hopes for their Pleistocene Park in Siberia, missing only its mammoth.
That idea of taint remains strong in people’s minds, but it shouldn’t, argued conservation scientist Kent Redford. Idealizing genetic purity of species is a purely human construction, ignoring the fact that even we are not pure, bearing evidence in our DNA of breeding with Neanderthals, Denisovans, and perhaps other yet unknown extinct hominids. Is a bison that bears cattle DNA in the American West any less of a bison? The future belongs to such hybrids. Redford concluded. “I am less concerned about the details of de-extinction than the message of hope that it can carry.”
In fact, the great hope of de-extinction may be proved not by an animal but a plant, the American chestnut. As plant biotechnologist Bill Powell explained: one of four trees in the great North American forest of yesteryear would have been a chestnut, since felled nearly entirely by a fungal blight imported from Asia. “If you’re going to bring back species like the passenger pigeon, what are you bringing them back to? The forest’s not the same,” Powell noted. “You might want to bring the chestnut back before anything else.” His work splices genetic resistance to the disease into the American chestnut genome while colleagues attempt to breed the tree with its blight-resistant counterpart from China. Restoring the chestnut will be the work of generations for both natural and man-made reasons. “You and your children and your grandchildren need to help with this because it’s going to take a long time to bring it back,” Powell said.
Once the American chestnut is back, however, the hope is that the tree could take care of itself. That is not the case for the “poor man’s Jurassic Park” tended by paleobiologist David Burney on the Hawaiian island of Kauai. Trying to keep invasive plants out of this native plant garden puts one on the “weed treadmill,” unless one enlists the help of animal species that can keep the weeds in check. So, for example, Burney employs giant tortoises (substituting for an extinct tortoise-billed duck) to clear the ground, with the added benefit of drawing more crowds and more support to the project. Even better, once the native plants began to thrive, the rare, native insects came back all on their own. “Do they smell it? I don’t know,” Burney said of this “Field of Dreams” effect. But “if you make an effort in the right direction, nature will sometimes help you.”
That has certainly proved to be the case in the most massive restoration project perhaps ever undertaken: the revival of the California condor. To bring the species up from just 22 birds left in the world to more than 400 today, a slew of techniques had to be developed by scientists like Michael Mace, including puppets to simulate condor parents as well as snatching eggs from condor nests to induce mothers to lay again, so-called double clutching. The result is majestic, massive condors soaring free once more in California and Arizona. And the price has been a constant vigilance, including annual booster vaccinations against West Nile virus. “It’s a rather momentous undertaking we have to do,” Mace admitted.
The same would no doubt be true for any de-extincted species. We now live in the Anthropocene, where humanity’s impacts extend all the way from geology to biology. Learning to manage the systems we once thought of as natural, whether climate or bird breeding, will be one of the greatest challenges our species has ever faced–and one of the greatest responsibilities we have ever shouldered. As Stewart Brand said in closing the event amid a gathering of all the speakers on the stage: “This is going to be an amazing century.”