Imagine arriving on Mauritius and a flock of dodo birds is greeting you on the island. Or, are you perhaps attracted to Siberia and its hairy mammoths? Maybe, Australia and the Tasmanian tiger, or New Zealand and the gigantic moa?!
The only problem is that these animals and birds are extinct. But, imagine they weren’t.
Although technology has advanced so much in the last several decades, it still hasn’t reached a point where died-out species would be brought back to life. Nevertheless, scientists don’t dismiss the idea as unlikely. The International Union for Conservation of Nature (IUCN), which ascribes an endangered status to species, believes that in the future, technology would develop to the point where de-extinction of species would be a genuine possibility.
The organization has already assembled a team of conservation experts to draft a pilot plan, published in May last year, which gives guidelines for bringing extinct species back to life.
Axel Moehrenschlager, director of conservation and science at the Calgary Zoo in Canada, and Phil Seddon from the University of Otago in New Zealand, both of whom are experts in re-introduction – bringing endangered species back to their natural habitats, are part of the IUCN team.
The project objective is not reviving extinct species for the purpose of exhibiting them in zoos, but reintroducing these species to their natural habitats, i.e. generating a genetically diverse population capable of surviving in the wild.
“We know from re-introducing existing species in areas where they’ve been missing for a while that you can have all sorts of unintended consequences,” Seddon explains.
Each species belonging to an ecosystem has a particular role. Grass-eaters, for instance, keep vegetation under control, while predators keep prey population in check.
According to Seddon, some species are less needed than others. “We’re still grappling with the idea of functionality in ecosystems but we do understand that some species are less redundant than others. De-extinction could be the art of trying to bring something back that would fill in the gap or serve the same purpose in that ecosystem.”
Reintroduction programs around the world generally follow IUCN guidelines to determine which species to work with and where to place them. Both Moehrenschlager and Seddon agree that the same model should be used when selecting species for de-extinction.
In 2014, they compiled a ten-question screening test for potential candidates. The questions included causes of extinction, habitat needs and the impact and potential risks of re-introduction.
For instance, if the causes of extinction are unknown, it’s almost certain that we won’t be able to protect this species from extinction after it’s been brought back to life.
Or, is there a suitable habitat for the species we want to de-extinct and will it be available in the future? To answer this question, conservationists need to fully understand climate, physical space and food requirement of the candidate species.
Finally, is it possible to control the outcome and potential risks? Reintroducing a species could affect current populations in the ecosystem. One of the risks includes spread of diseases that could be passed on both animals and people. How would we cope with such a scenario?
This long test must be taken before any decision is made regarding the de-extinction of a species.
“If you fail the test, you’re out,” says Moehrenschlager, “but if you pass, you’re only good enough to go to the next stage of assessment.”
So far, three potential candidates have been assessed for de-extinction, among which, the Tasmanian tiger or thylacine.
The last Tasmanian tiger died in 1936. Hunting, habitat loss and lack of prey are some of the contributing factors to its extinction. This animal inhabited mixed forest, wetlands, and coastal heath, parts of which are still intact. As a matter of fact, these areas have been protected in order to ensure territory for the Tasmanian tiger. Besides, there are no records that this species carried diseases, so its resurrection shouldn’t cause any disapproval except from farmers who might lose a sheep or two.
How far are we from a de-extinction technology? The truth is that some attempts have already been made.
In 2000, a Pyrenean ibex was cloned from cells taken from the last surviving specimen. But, this attempt failed as the clone died 7 minutes after birth due to lung failure.
It’s also important to bear in mind an often neglected fact – true de-extinction is impossible. None of the methods scientists are currently considering can result in a carbon copy of the extinct animal. The best they can do is provide a substitute for the species.
One method – a selective back-breeding allows researchers to work with a species that is linked to the extinct species. In other words, scientists choose individuals with traits that resemble those seen in the extinct species and selectively breed them. Then they choose the offspring that have slightly more developed versions of those “extinct” traits and selectively breed them, and so on. The end result is a population that physically resembles the extinct species, although their genetics is different.
Somatic cell nuclear transfer, or cloning can be performed only with species that recently died out and whose tissues are well preserved. It can be used with healthy animal populations too; the famous sheep Dolly, for instance.
Genetic engineering is crucial if scientists want to resurrect a species that died out long before adequate samples could be preserved. The thing is DNA disintegrates over time, and the older the biological material, the more difficult it is to assemble all the pieces of the DNA. In case of any missing pieces, the gaps will be filled with parts of genome from a related living species.
Both cloning and genetic engineering result in an embryo that depends on a surrogate mother – one from a species as closely related to the extinct one as possible. But, this also contributes to the modification of the resurrected species.
When a ‘resurrected’ mammoth is born, it’s the only one of its kind. How will it learn to be a mammoth if raised by people or elephants?
A substitute for an extinct species can be genetically close to the original, it terms of behavior, but it’ll never be identical. In other words, de-extinction is not a method that can undo the adverse ecological consequences of human action.