Reviving extinct genetic diversity #Resurrection Ecology
Is it time to define a new field?
By Nadine Lymn, ESA public affairs director
This is the first in a series of EcoTone posts on a recent TEDxDeExtinction event. You can watch the presentations, hosted by the National Geographic Society, here. The talks will be edited and posted to YouTube in a few weeks. NGS showcases de-extinction in the lead story of its April issue here.
“Maybe it’s time to coin a new term,” said Stanley Temple, a long-time conservation biologist who played key roles in preventing species such as the Peregrine Falcon and Whooping Crane from going extinct. We were already well into the ‘Why & Why Not’ portion of TEDxDeExtinction on Friday, March 15, and it was clear that Temple, the man who occupied Aldo Leopold’s chair at the University of Wisconsin for 32 years, has deep reservations about reversing extinction through genetic engineering. But he also clearly believes that conservation biologists need to be part of developments as the quest to revive extinct species inevitably moves forward. Thus: “Resurrection Ecology.”
Update [3/21/13, 4 PM] Temple told me he misspoke and meant to say “Resurrection BIOLOGY” since resurrection ecology has been applied to a different topic–limnologists who dredge up eggs from lake sediment to reconstruct past community structure.
After listening to 6 hours of TEDxDeExtinction presentations last Friday, my head was spinning with gripping stories of charismatic and extinct species such as the Thylacine (a meat-eating marsupial—its name means dog-headed, pouched one), the biological, ethical and political dilemmas of “bringing back” species, and descriptions of the genetic techniques underway to make this is a reality.
Several themes threaded throughout the event. Here are two of them that are closely intertwined: 1. A strong concern that revival of extinct species could make current efforts to save endangered species even harder, and 2. The potential for gene technology to help save today’s endangered species.
To the first theme:
“We’ve got our hands full” trying to save what’s still here now, said Stanley Temple. Temple, a professor emeritus at the University of Wisconsin, is worried that de-extinction efforts could destabilize already difficult conservation efforts. We already have a tendency to rely on technological “fixes”, he said. If extinction isn’t forever, then the attitude could become, ‘let it go extinct, we can always bring it back later.’
But are too many of us already either unconcerned or feeling helpless about the many species slipping into extinction? Would revival of extinct species give a green light to a more cavalier attitude towards loss of species?
Rutgers University biology professor David Ehrenfeld wants people to consider this: While some are talking about bringing back the woolly mammoth, others are risking their lives to try to save its close relative, the African elephant, which is threatened by poaching.
Ehrenfeld, the founding editor of the scientific journal Conservation Biology is not only extremely concerned about the potential distraction from conservation efforts, he is also deeply skeptical that species that might be “brought back” would be anything like the original species. He pointed to the multitude of ways in which a DNA strand may be interpreted and the interplay of internal and external stimuli which direct how it shapes an individual. In addition, extremely social species would present a further obstacle. The complex behavior of the highly gregarious passenger pigeon, for instance, would make bringing this extinct bird back a huge stumbling block. “The more complex, the more difficult to predict the consequences,” said Ehrenfeld.
Temple and Ehrenfeld also noted that for species that have been gone for a long time, the environments in which they lived have changed and established a new dynamic equilibrium. That could mean that we “revive” a species that would be completely dependent on us to survive if its former habitat will no longer support it.
However, in recognition that revival efforts are already underway, Temple suggested that perhaps it’s time for “Resurrection Ecology” –applying ecological principals to decide which species should be brought back from extinction.
What would be on your list?
Temple suggested that good candidates—from an ecological perspective—would be recently extinct species such as the Thylacine, lost to direct killing endorsed by the Australian government, and the Ivory-billed woodpecker, extinct because of habitat loss. The things that drove them to extinction are no longer an issue.
Conservation biologists know techniques (captive breeding and reintroduction of rare species) that would be helpful to future deextinction efforts, said Temple. But his and Ehrenfeld’s message was clear: our priority should be existing species.
Which brings us to the second theme: that of using genetic techniques to help species that are still with us, but are in trouble. Some species are in a genetic bottleneck—so few individuals remain that their collective genetic make-up is impoverished, making the species highly susceptible to dying out. An example is the white rhino, where only seven, closely related, individuals remain. “It seems to me we’re in a race,” said Oliver Ryder, Director of Genetics at the San Diego Zoo. He advocates using genetic technology to introduce more diversity into such rare species. Ehrenfeld said that the best contribution of gene technology would be to bring viable genetic variation into still living but rare species. Temple echoed the sentiment that reviving extinct alleles could “help some rare species have a more secure future.” Alleles are alternative forms of the same gene and are essential in providing variety in a species population to give it the best chance in coping with diseases and with other things or events it may encounter in its environment. Species like the white rhino or black-footed ferret have lost so much genetic diversity that they are vulnerable to any one event wiping them out completely. Reviving extinct alleles could help species like these.
Kate Jones, an ecologist at the University of London, admitted an initial horror at the thought of reviving extinct species. But she sees exciting potential for synthetic biology to help save species that are threatened by emerging diseases. An example is the devastating impact the chytrid fungus has had on amphibians, especially frogs. During the event’s lunch break, I sat next to a scientist who works for the National Zoo, who told me about the Amphibian Ark, which is trying to ensure the survival of amphibians that can’t be safeguarded in nature because of the chytrid fungus. Genetic technology might be a way to turn things around for frogs and other amphibians.
Temple said he was very curious to see what the reaction from National Geographic readers will be about the magazine’s April cover story on reviving extinct species.
More posts to come, exploring additional aspects of the TEDeExtinction event…