De-extinction

De-extinction, also known as resurrection biology or species revivalism, is the process of human intervention to create an organism that resembles an extinct species. This scientific field seeks to use advanced technology to bring back life forms that no longer exist in the wild.

While the concept of using genetics to recreate landscapes has dark historical roots in the Nazi era, the modern term arose in the twentieth century following major biological breakthroughs. Today, scientists study various methods to achieve this goal, ranging from high-tech genetic engineering to traditional selective breeding. The ultimate aim is often to restore lost biodiversity or to repair ecosystems damaged by human activity.

One of the most direct methods is cloning, which aims to produce an organism with the same nuclear genome as the original. To perform cloning, scientists extract the nucleus from a preserved cell of the extinct species. They then swap this nucleus into an egg cell of a closely related living species that has had its own nucleus removed. This egg is implanted into a surrogate mother to develop.

This method requires well-preserved, viable donor cells, making it most feasible for species that went extinct recently. The Pyrenean ibex remains the only animal to have survived de-extinction past birth through this specific process. Scientists used tissue from the last living female, Celia, to attempt this revival.

Another sophisticated approach involves genome editing, specifically using the CRISPR/Cas9 system. CRISPR stands for clustered regularly interspaced short palindromic repeats, which was originally discovered as a bacterial immune system. In bacteria, viral DNA is incorporated into the chromosome, and the Cas9 protein acts like a pair of molecular scissors to recognize and cleave that foreign DNA.

Scientists can use these "scissors" to edit the cells of a closely related living species. By targeting specific adaptive traits, they can create a hybrid or proxy that looks and acts like the extinct species. This method is useful because it can work even with highly degraded DNA from old tissues, though fragmented DNA makes the assembly process much harder.

Selective breeding, or back-breeding, offers a different path that does not require genetic reconstruction. Instead of using preserved cells, scientists look for ancestral characteristics that still appear occasionally in modern populations. By deliberately breeding animals that show these traits, they attempt to recreate the phenotype, or physical appearance, of a wild ancestor.

While this can produce animals that look like their extinct relatives, the resulting genome will be different. These animals may also lack the specific behaviors, physiological functions, or ecological roles of the original species. The Taurus Project is an example of this, aiming to recreate the aurochs through the breeding of modern cattle.

Nature itself sometimes performs a version of de-extinction called iterative evolution. This occurs when a species goes extinct, but a different species later evolves into an almost identical creature.

For instance, the flightless Aldabra rail went extinct about 136,000 years ago when sea levels rose. When sea levels dropped 100,000 years ago and the island reappeared, the white-throated rail recolonized the area. Eventually, it evolved into a flightless species that was physically identical to the extinct one. Unlike human technology, iterative evolution is a natural process, but it is unpredictable and cannot be controlled or timed by scientists.

There are significant advantages and serious risks associated with these technologies. On the positive side, advances in cloning could help prevent currently endangered species from vanishing. Revived species could also act as "flagship species," helping to raise public interest and funding for entire ecosystems.

However, the costs are immense, often reaching millions of dollars per species. There is a concern that this funding could be taken away from current conservation efforts for animals that are still alive. Furthermore, a reintroduced species might become invasive, competing with existing animals for food or introducing new diseases to which they have no immunity.

Finally, de-extinction raises profound ethical and legal questions. If scientists were to recreate species with high cognitive abilities, such as Neanderthals, it would create massive moral dilemmas. Such beings might possess self-awareness and the capacity for suffering.

Without specific legal protections, these individuals might be treated as mere research tools rather than sentient beings. As science moves forward, society must decide how to balance the wonder of resurrection with the responsibilities we owe to both new and existing life.