De-extinction

De-extinction as a concept involving genetics traces back to the Nazi-era eco-fascist efforts "integral to recreating the mythical German landscape of ancient times, when the Aryan race was pure and unthreatened", but the term itself arose in the twentieth century "in response to a series of breakthroughs in resurrection biology".

One example of this was the work done by Berlin zoo director Lutz Heck, in collaboration with his brother and Munich zoo director Heinz Heck, to bring aurochs back from extinction through a process of selective breeding. Their work was condemned by the Union of German Zoo Directors in 1951, when they stated "that their organization would offer no financial or other support for breeding back extinct species since it was not only a scientific impossibility but took away resources from the pressing issue of preserving threatened animals."

Cloning is a commonly suggested method for the potential restoration of an extinct species. It can be done by extracting the nucleus from a preserved cell from the extinct species and swapping it into an egg, without a nucleus, of that species' nearest living relative. The egg can then be inserted into a host from the extinct species' nearest living relative. This method can only be used when a preserved cell is available, meaning it would be most feasible for recently extinct species. Cloning offers the most direct route to an organism with the original species' nuclear genome, but it requires well-preserved viable donor cells. Cloning has been used by scientists since the 1950s. One of the most well known clones is Dolly the sheep. Dolly was born in the mid-1990s and lived normally until the abrupt midlife onset of health complications resembling premature aging, that led to her death. Other known cloned animal species include domestic cats, dogs, pigs, and horses.

Genome editing has been rapidly advancing with the help of the CRISPR/Cas systems, particularly CRISPR/Cas9. The CRISPR/Cas9 system was originally discovered as part of the bacterial immune system. Viral DNA that was injected into the bacterium became incorporated into the bacterial chromosome at specific regions. These regions are called clustered regularly interspaced short palindromic repeats, otherwise known as CRISPR. Since the viral DNA is within the chromosome, it gets transcribed into RNA. Once this occurs, the Cas9 binds to the RNA. Cas9 can recognize the foreign insert and cleave it. This discovery was very crucial because the Cas protein can now be viewed as a scissor in the genome editing process.

By using cells from a closely related species to the extinct species, genome editing can play a role in the de-extinction process. Germ cells may be edited directly, so that the egg and sperm produced by the extant parent species will produce offspring of the extinct species, or somatic cells may be edited and transferred via somatic cell nuclear transfer. The result is an animal which is not completely the extinct species, but rather a hybrid of the extinct species and the closely related, non-extinct species. …

The concept of de-extinction is often met with skepticism, as it presents both significant advantages and disadvantages. Some may believe that extinction is a natural evolutionary process, but the 21st century has been marked as the sixth major extinction event in Earth's history. We have reached unprecedented speed and scale at which species are disappearing. Up to half of the species on Earth are predicted to disappear this century. The scale at which we are losing species is important to the ethical stakes de-extinction presents. This is overwhelmingly caused by human activity (habitat destruction, pollution, invasive species, climate change), not natural processes like previous extinctions. Since humans are the primary cause of this modern extinction, it can be argued that humans now have the moral obligation to repair it. The loss in species variation (biodiversity) is not a result of survival of the fittest, but the negative consequences of human interference with the planet.

With this in mind, reviving species lost through human actions may help restore biodiversity and address harms humans have caused to the planet. De-extinction can be viewed as an unnatural interference, while also showing potential as a tool for ecological restoration. Reviving species could be part of ecological restoration and ethically defensible.

The technologies being developed for de-extinction could lead to large advances in various fields:

Prioritising de-extinction could lead to the improvement of current conservation strategies. Conservation measures would initially be necessary in order to reintroduce a species into the ecosystem, until the revived population can sustain itself in the wild. Reintroduction of an extinct species could also help improve ecosystems that had been destroyed by human development. It may also be argued that reviving species driven to extinction by humans is an ethical obligation.

The reintroduction of extinct species could have a negative impact on existing species and their ecosystem. The extinct species' ecological niche may have been filled in its former habitat, thus making them an invasive species. This could lead to the extinction of other species due to competition for food or other competitive exclusion. It could also lead to the extinction of prey species if they have more predators in an environment that had few predators before the reintroduction of an extinct species. If a species has been extinct for a long period of time the environment they are introduced to could be wildly different from the one that they can survive in. The changes in the environment due to human development could mean that the species may not survive if reintroduced into that ecosystem. A species could also become extinct again after de-extinction if the reasons for its extinction are still a threat. The woolly mammoth might be hunted by poachers just like elephants for their ivory and could go extinct again if this were to happen. Or, if a species is reintroduced into an environment with disease for which it has no immunity, the reintroduced species could be wiped out by a disease that current species can survive.

De-extinction is also a very expensive process. Bringing back one species can cost millions of dollars. The money for de-extinction would most likely come from current conservation efforts. These efforts could be weakened if funding is taken from conservation and put into de-extinction. This would mean that critically endangered species would start to go extinct faster because there are no longer resources that are needed to maintain their populations. Also, since cloning techniques cannot perfectly replicate a species as it existed in the wild, the reintroduction of the species may not bring about positive environmental benefits. They may not have the same role in the food chain that they did before and therefore cannot restore damaged ecosystems.

De-extinction also presents serious ethical challenges, particularly if applied to species with high cognitive abilities such as Neanderthals. If such beings were recreated, they might possess capacities for suffering and self-awareness, raising difficult questions about their rights and moral status. …