New Zealand’s extinct huia, a beautiful, gentle, friendly bird, is the rare case where de-extinction might make sense, says Douglas Campbell at New Zealand’s University of Canterbury. It’s culturally important to the Maori people and is such a bad flyer that it could be easily contained. [Image Credit: Wikimedia Commons user DrJunge | CC BY-SA 3.0]
If movies about bloodthirsty dinosaurs were to teach us anything, it’s perhaps that extinct species should stay that way.
Yet formerly extinct animals may once again lumber, crawl and scamper across the land. The technology that would allow de-extinction — the resurrection of plants and animals that died off one way or another — is not far off. Techniques such as cloning and selective breeding could bring back or create approximations of organisms from tissue samples, possibly including ancient animals such as the woolly mammoth. Resurrecting dinosaurs like in the Jurassic Park films, which were partially-inspired by the work of real-life paleontologist Jack Horner, is an unlikely application of de-extinction. But advocates of the process think that it could restore balance to damaged ecosystems or inspire broader conservation policies and activities.
For instance, Douglas Campbell, a philosopher at New Zealand’s University of Canterbury advocates resurrecting New Zealand’s extinct huia, a beautiful, mostly flightless bird of cultural importance to the island’s indigenous Maori people. Although Campbell thinks that still-living-but-endangered species should take priority over the huia when it comes to conservation efforts, he says that there’s value in resurrecting animals simply because people like them. He argues that bringing back a charismatic, beautiful bird like the huia could be the key to convincing local farmers to convert their land back to natural bush and convincing both policymakers and the public to dedicate time and money to conservation.
“We shouldn’t be embarrassed by trying to push for charismatic species,” says Campbell, although he also agrees that cultural value shouldn’t be the deciding factor when it comes to species resurrection. He also notes that the nearly flightless huia is easily contained in the event it causes damage to its modern ecosystem — which would have changed since the bird vanished — unlike other candidates for de-extinction.
This case-by-case approach is popular among those who are open to de-extinction. The best candidates are “[not those that have] the greatest potential for reintroduction, but the greatest potential to reintroduce without disrupting ecosystems,” says Dennis Murray, a conservation ecologist at Canada’s Trent University.
Murray found that one candidate, the ivory-billed woodpecker, widely-assumed to be extinct, may be a good fit for de-extinction because its highly-specialized ecological niche has remained vacant in the bird’s absence. There’s room for the woodpecker to live and it’s less likely to disrupt other species in the area. But this is a rare case.
More common is the case of the passenger pigeon, which would require a great deal of space to migrate and could severely disrupt and displace other animals in the area. “Things that can’t readily be contained, unless we have a real strong ecological need to have them back in the system, shouldn’t be reintroduced,” says Murray, discussing how many of these ecosystems have adapted and are doing just fine without the extinct species. “I’m not convinced that by throwing passenger pigeons out there we’re going to restore a more natural state.”
Murray’s requirements for de-extinction are that there’s enough habitat for the resurrected species to live in, a vacant niche for them to fill and a good chance that the plan won’t backfire.
Meeting these requirements is a tall order. Murray’s recent work examines the impact that de-extinct species might have on living species, especially now that climate change has pushed some of the latter into new territory. The reintroduced organisms could act as an invasive species that displaced extant species already challenged by living beyond their historic ranges or in ecosystems where the extinct species’ niche has since been filled.
Murray acknowledges that the potential for bringing back extinct life is stoking enthusiasm, but he cautions rash de-extinction decisions. “Everyone’s excited — it’s moving science forward,” says Murray. “People are getting wrapped up in [the new technology] without thinking about the impact of releasing species on the ground.”
And then there are the technical challenges. “[De-extinction is] a fantastic technology, but I think it’s unlikely to work, to be honest,” says Thomas Gilbert, a paleo-geneticist at the Natural History Museum of Denmark.
Gilbert’s lab studies ancient DNA, and his work has led him to believe that true de-extinction may never occur, at least not that of ancient animals where a viable tissue sample is hard to find. “All ancient DNA is crap,” Gilbert said, explaining that the problem with these samples isn’t their age but rather how quickly some of the relevant genes evolve compauired to others.
If a mammoth sample contains an incomplete genome, for example, the missing parts could be replaced with elephant DNA. But these filler genes could be totally divergent from their common ancestor, causing unwanted mutations. “If these genes do something and we’ve only got the elephant version, we don’t know how that will screw things up,” Gilbert says. Unfortunately, it logically follows that any rapidly-evolving gene — those that would have changed more drastically from the genes of a common ancestor, making them unique to the extinct animal and replaced with filler — is going to be more important when it comes to differentiating among related species and resurrecting the extinct animal as it truly was.
“My concern is that we will never have a perfect reconstruction. And then the question is what did those missing bits do?” Gilbert asked. Rather than fully ruling out de-extinction, Gilbert feels that scientists should fully evaluate their goals and define the threshold of success accordingly.
If the end goal of de-extinction is to bring back an organism for cultural or ethical reasons, then a perfect genetic match would be necessary. But if it only matters that the resurrected animal looks or acts like the extinct species, then the genetics are less important.
He gives the example of the quagga, a distinctly-patterned subspecies of the zebra that was resurrected via selective breeding by a project that started in 1987. “It’s not really [a quagga] but it looks like it. The genetics is irrelevant because people are going to pay money to go and look at it,” Gilbert says.
Similarly, if mammoths were resurrected for display in a zoo or a protected area accessible only to tourists on safari, then it only matters that one breeds an elephant that looks like its extinct cousins. Or if animals are brought back to fill vacant ecological niches — the more common argument of conservationist de-extinction advocates — then what’s really needed is some animal that can fill that role. Rather than recreating a genetically-whole mammoth, a cold-resistant elephant-mammoth hybrid would do just fine.
“Let’s try to generate as good an ancient DNA as possible, see what bits are missing, and then have a thought experiment about how successful we are,” says Gilbert, describing an idealized approach to de-extinction.
University of Canterbury philosopher Campbell agrees. “If all you want is ecological function, then there’s no need to go beyond that,” he says. “A hairy elephant would be enough.” Some genes matter, some genes don’t, he says. “We probably shouldn’t be trying to create perfect copies.”
Still, there’s the legal arena. The place of de-extinct animals in the landscape of conservation law is under-theorized, says Alejandro Camacho, an environmental lawyer at University of California, Irvine School of Law. “People from the law side are looking at whether or not we can legally do the biotechnology,” he says, “and aren’t paying attention at all to how conservation law might affect it.”
For instance, the Endangered Species Act could complicate the case for de-extinction. “If you look at the law, it’s at best unclear if the de-extinct species would be considered endangered,” he says.
Rather than looking at the risks and benefits of reintroduction based on current and expected ecological conditions, as Camacho argues that the law ought to, our conservation policies focus more on protecting natural ecosystems over those that have been altered by humans, like cow pastures. This distinction is arbitrary, so it is unclear whether resurrected species — and their migratory patterns — would be viewed as natural and need protection, or if they are man-made Frankensteins that don’t merit conservation attention. Because these issues with the law have yet to be navigated, Camacho argues that the situations in which de-extinction would be the best conservation approach will be rare.
So is de-extinction good or bad? It depends, Campbell says. He feels that preserving tissue samples for future use — while addressing more pertinent conservation issues — would greatly benefit society a century down the line.
Camacho has serious doubts. “I think the de-extinction folks who are gung-ho have blind spots,” he says.
The idea of cloning a woolly mammoth, which periodically ebbs and flows in the news cycle, is cool. And there’s nothing wrong with working to further biotechnology or conservation efforts, but at best, de-extinction is poorly thought-out. At worst, it could be ecologically devastating.
Most experts are calling for more holistic thinking about even near-future scenarios.
“People have been very interested in the front end of the process — developing the techniques necessary to make this happen — but people have really forgotten to look at the back end,” says Murray. “We need to do our due diligence, and that part has not caught up to the technologies of cloning. We have completely ignored that aspect.”