Does Extinction Have to be Forever?

The last remaining thylacine died in captivity in 1936, rendering its species extinct. Also known as the Tasmanian tiger, it was a large carnivorous marsupial that lived in Australia, New Guinea and Tasmania.

On September 1, 1914, a passenger pigeon named Martha died at the Cincinnati Zoo, the last of a species that filled the skies in flocks a mile wide and hundreds of miles long just a handful of decades earlier.

In 2000, the last Pyrenean ibex was killed, a species of wild goat that had been common in France and Spain for tens of thousands of years.

Extinction has been a reality of nature since life began. It happens for a range of reasons, but all of these animals went extinct due to the impact of human beings on their environment and they are hardly the only ones. Human activities have wiped out many hundreds of animal species over recent centuries. It is a tragic loss that shrinks biodiversity, damages the earth’s ecosystem and destroys the outcome of tens of millions of years of evolution. As we look ahead at the future of our planet, it should be apparent that such a path is not sustainable.

Recognizing the importance of these species, a number of people have been working in recent years on efforts to bring some of these species back. De-extinction, sometimes known as resurrection biology, is seen as increasingly possible because of recent advances that have been made in fields like genomic editing, cloning and biotechnology.

De-extinction is seen as having many other benefits beyond making amends for our past. For instance, the hardware, software and wetware being developed will have major uses for both nature conservation and human health. Tools to quickly analyze and check gene edited cells, as well as new in vitro fertilization techniques are just two examples.

The dream of bringing back extinct species is one that many scientists and researchers share. The nonprofit wildlife conservation organization, Revive & Restore was co-founded by Ryan Phelan and her husband, Stewart Brand to support this cause. The organization promotes a range of tools and practices designed to augment traditional conservation practices with a "Genetic Rescue Toolkit" designed to support recovery through biotechnology methods. A conference they helped organize in 2012, drew biology researchers from all over the world, many of whom hadn’t realized there were many others with similar interests in de-extinction. Many new partnerships and collaborations resulted from the event.

Colossal Biosciences is also working to advance the field of de-extinction, focusing on a number of species, including thylacines, the dodo, and one day, perhaps even the woolly mammoth. Since some of these are classified as keystone species, their role is considered to have been crucial to their former ecosystems.

Colossal was co-founded by entrepreneur, Ben Lamm, and renowned molecular geneticist, George Church, who helped initiate the Human Genome Project in 1984. Working with a team of genetic scientists, they've pioneered a number of strategies and techniques to try to bring back various species.

While cloning is used in some of their techniques, there simply isn't complete enough viable genetic material needed to clone most species back into existence. Instead, other techniques such as gene editing using CRISPR-Cas9 and back-breeding – hybridization to recover lost traits – are considered much more feasible. The end result will be the re-creation not of the exact species, but one very like it. This would almost certainly be the case with work to recover the woolly mammoth.

Even once most or all of an animal's genetic material is recovered, however, many substantial hurdles will remain. Eggs will need to be fertilized and implanted in a similar enough species to carry it to term. Since elephants have a gestation period of nearly two years, it makes sense to do early research and testing on species that have far shorter pregnancies.

The world’s first successful de-extinction was in 2003, when a Pyrenean ibex, also known as a bucardo, was cloned from stored genetic material. Though the goat only lived a short time after being born, it showed this approach is possible.

The concept of de-extinction is not without its controversies. Apart from the inevitable comparisons to the highly fictionalized world of Jurassic Park, there are far more real concerns to consider. Since funding for this work can come from the same sources as more traditional forms of conservation, many are worried this will impact those efforts.

Then there are the realities of time and the changing environment. The ecosystems these species once thrived in no longer exist. Will the potential recovery and reintroduction of the extinct species disrupt those ecosystems, perhaps even driving other species to extinction in the future?

In the case of restoring the wooly mammoth, this is a highly intelligent mammal with a very long gestation period. Can the work be ethically justified given these circumstances?

Of course, there is inevitably the argument that in doing this, we are somehow playing God. But as advocates point out, weren't we already doing this when we altered the environments to such a degree that it brought about these extinctions in the first place? Since the agrarian revolution we’ve routinely hybridized plants and animals, altering and domesticating them for our benefit. In a manner of speaking, that horse is out of the barn.

The idea of de-extinction is not without its challenges, but it also holds huge hope for restoring and re-balancing the damage we've caused to nature across the centuries. Who knows? Perhaps one day we’ll look back at all the species we’ve saved and wonder how we ever could have lived without them?