Will Dead Species Live Again?
It sounds like science fiction - but it could happen in real life. Stan Temple describes "de-extinction" and its promsie for conservation.
Stanley A. Temple is the Beers-Bascom Professor Emeritus in Conservation in forest and wildlife ecology at CALS and a former chair of the conservation biology and sustainable development program at the Gaylord Nelson Institute for Environmental Studies. For 32 years Temple occupied the faculty position once held by Aldo Leopold, and while in that position he received every University of Wisconsin teaching award for which he was eligible. Since his retirement from academia in 2008 he has been a Senior Fellow of the nonprofit Aldo Leopold Foundation. He and his 75 graduate students have worked on conservation problems in 21 different countries and have helped save some of the world’s rarest and most endangered species. Last spring Temple gave a TED talk at a special event devoted to de-extinction, a concept that has captured the imagination of scientists and the general public alike.
What is “de-extinction”?
De-extinction is a recent term that involves bringing back an extinct species using DNA that’s been recovered from preserved material. There are two ways that it can be accomplished: one would be cloning to produce a copy of an extinct individual’s genome. The second way is through genetic engineering to re-create a close approximation of what the extinct species’ genome might have once been. The reality is that it’s no longer science fiction. We’re getting close to being able to revive extinct species from recovered DNA.
This must make for some unusual scientific partnerships.
It’s an interesting synthetic endeavor that matches the biotechnologists in the laboratory with conservationists in the field. The biotech crowd will be responsible for recovering DNA from an extinct species and through either cloning or engineering turning that DNA into individuals. But once they’ve done that, the next step involves people like myself who know how to recover endangered species by taking a small number of individuals and turning them into a viable population and getting them back into the wild.
What opportunities might this technology present to conservation efforts?
On the plus side, obviously, it would be exciting to bring back a species that human beings drove to extinction. But even if we weren’t able to do that, the technology presents an appealing opportunity to recover DNA from preserved specimens of an endangered species and use it to enhance the genetic diversity of the surviving population.
Can you please elaborate on that?
Conservationists have recovered many endangered species from very low population levels and saved them from extinction. The problem is, they’re often genetically depauperate, or lacking in genetic diversity. If we can recover some of the lost genes from preserved specimens collected before the population crashed, we might greatly improve the species’ prospects for long-term survival.
How would a conservation biologist go about actually applying this?
De-extinction is still an unproven concept, but it’s likely that sometime in the coming decades it will happen. Once they have revived individuals of an extinct species in the lab, then conservation biologists could try to recover the species by captive breeding and reintroducing the species to the wild. But conservation biologists get concerned about some of the details: Which species are going to be revived? Are they the right species? Are they the species that have the best chances for long-term survival in the world today? Are they species that might actually enhance the ecological health of the ecosystem that they were once part of, like the wolves reintroduced to the Yellowstone ecosystem? These are all questions of setting priorities for which species to actually revive.
How would you recommend setting priorities?
As a conservation biologist I would certainly look first at recently extinct species that were affected by a threat we’ve now overcome. Not only are those the ones for which we’re likely to have good quality DNA, but their ecological niche in the wild hasn’t been vacant for very long. And as a result, the ecological community that they were once part of has not readjusted itself to their absence, and might once again easily accommodate the species in its midst. On the other hand, if you’re dealing with a species that’s been extinct for a very long period of time—centuries or even millennia—the ecosystem that they were part of has moved on, and a species like that, once back in the system, could essentially be the equivalent of an invasive species. It might disrupt the system and threaten extant species.
How would you like to see this development proceed?
Considering the timeline that we probably have years or even decades to do this right—I and other individuals and groups that are thoughtful and somewhat skeptical about this would like to see a very broad discussion of the implications. We would like to see a lot of input in deciding the priorities about which species to bring back. We would not like to see this done in secret, which, unfortunately, is where this seems to be heading. This very expensive work is not receiving government funding and doesn’t have any sort of public oversight. Hence, privately funded biotech labs seem to be focusing on reviving spectacular extinct species, like mammoths and other Ice Age animals, rather than species that have a real chance of surviving in today’s world.
What would be an important takeaway point for the general public?
De-extinction doesn’t mean we can ignore the significance of extinction—to think, “Oh well, we can let species go extinct because we can always save some DNA and bring them back later.” This would just be an open door for activities that have been constrained by concerns for biodiversity and basically give the green light to go ahead and precipitate extinctions of species that are already with us.
Let’s visit the process of extinction a little more generally. What does it mean to us?
One of the catchphrases is “extinction is forever.” And for three and a half billion years of life on this planet, that has been true. No species that has gone extinct has ever come back. So de-extinction would be an unprecedented biological event.
But extinction—the death of the last individual of a species—is of course a natural process. It eventually happens to all species in the course of their evolution. But we have greatly accelerated the rate of extinction in recent times because of human activities, so that compared to the long history of life on this planet, we’re in what is often referred to as a period of “mass extinction,” in which extinction rates are many orders of magnitude higher than they would normally be. And that is why the modern conservation biology movement has made such a push to make society aware of the fact that we are in a crisis right now of losing species from this planet—and, biotechnology notwithstanding, those that are being lost are gone forever.
You’ve worked with species that were close to extinction. Do you have a story about your favorite one?
Early in my career, on the island of Mauritius in the Indian Ocean—the former home of the extinct dodo—the Mauritius kestrel, a small falcon, was down to four individuals. As a young conservation biologist, capturing some of the last remaining individuals and bringing them into captivity, I knew that if something went wrong and the species went extinct, I would carry it with me throughout my career. Fortunately, things went well. There are now several hundred Mauritius kestrels. The same is true of the California condor, which dropped to 22 birds when my students and I worked with them. Now there are several hundred. So by and large, if we decide we really want to save a critically endangered species, we’ve generally been able to pull it off. The problem is, there are so many endangered species out there that need to be saved that we simply don’t have the resources to save all of them.
A CALS podcast with Stan Temple is available at http://go.wisc.edu/qgt6h8
His TED talk is posted at http://go.wisc.edu/0xh379