De-extinction

Some animals have gone away forever.

Scientists want to bring them back. This is called de-extinction.

One way is to use cloning. This makes an animal like the old one. It needs a tiny part from the old animal.

Another way is to breed animals. People pick parents with special traits. They want the babies to look like the old kind.

Scientists also use tiny tools. These tools can change parts of a cell. This can help make a new animal.

This work costs a lot of money. It can also change how nature works.

It is a big idea to think about.

Some animals have gone extinct. This means they are gone from the wild. Scientists want to bring them back. This work is called de-extinction.

One way to do this is cloning. Scientists take a tiny part from a preserved cell. They put it into an egg from a close relative. Then, a surrogate mother carries the baby. This makes an animal with the same genes.

The Pyrenean ibex is the only animal to survive past birth this way.

Another way is genome editing. Scientists use a tool called CRISPR. It works like tiny scissors to change DNA. This can make a hybrid animal. A hybrid is a mix of two kinds.

People also use back-breeding. This is a way of selective breeding. They pick parents with old traits. They want the babies to look like the ancestor. This does not change the genes. It only changes how they look.

De-extinction is a big idea. It can cost millions of dollars. It might also change how nature works. New animals might fight for food with living ones.

De-extinction is a way for humans to try and bring back living things that have died out. This work is also called resurrection biology or species revivalism. Scientists want to create an organism that looks or acts like an extinct one.

This process could help us fix mistakes made by humans. It might also help us learn how to protect animals that are still alive today. Some people think reviving species could even help fix broken ecosystems.

There are many ways this work might happen. Cloning is a popular idea because it creates an animal with the same genetic identity. To do this, scientists take a nucleus from a preserved cell of the extinct animal. They put that nucleus into an egg from a close living relative. Then, a surrogate mother carries the baby to birth.

Another way is genome editing using a tool called CRISPR. This tool acts like tiny scissors to cut and change DNA. This method often creates a hybrid, which is a mix of two different species.

Scientists have used cloning for a long time. They have been working with this method since the 1950s. One famous example is Dolly the sheep, who was born in the mid-1990s.

Dolly lived a normal life until she had health problems that looked like premature aging. Other animals that have been cloned include domestic cats, dogs, pigs, and horses. The Pyrenean ibex is the only animal to ever survive de-extinction past birth. This happened using a female named Celia to provide the tissue.

There are many different animals that scientists study for this work. The aurochs is a large bull that lived across Eurasia and North Africa.

It was even painted in famous French cave paintings like Lascaux. The woolly mammoth is another huge candidate for cloning. Some scientists even look at plants using old herbarium specimens. They try to see if they can wake up tiny embryos inside old seeds.

This could bring back plants that have not been seen for a very long time.

This work brings up many hard questions and big risks. It can cost millions of dollars to bring back just one species. This money might be better spent protecting animals that are still alive.

Bringing an animal back could also hurt the animals already living there. A new animal might take food away from others or act like an invasive species. It might even bring new diseases to the area. We must think carefully about how these living things will fit into our world.

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.