Reversing Extinction

Bringing species × species MARYANNE PETERSEN—EYEEM/GETTY IMAGES a category of living things that is made up of related individuals (noun) The domestic turkey is one species of bird. back from extinction × extinction ENCYCLOPEDIA BRITANNICA/UIG/GETTY IMAGES the state of having disappeared from existence, especially for a species (noun) Overhunting led to the extinction of the dodo. may seem more like science fiction than reality. But scientists are close to being able to bring animals back from the dead.

The first major breakthrough in de-extinction happened about 15 years ago. A team of Spanish researchers collected tissue × tissue JOHN FEDELE—GETTY IMAGES a grouping of cells that forms part of a plant or animal (noun) The athlete strengthened the muscle tissue in her arms by exercising. from the last living Pyrenean ibex. It was a beige mountain goat. She was nicknamed Celia.

In South Africa, researchers are reviving QUAGGAS by breeding zebras that have quagga-like traits.

Scientists inserted Celia’s DNA into the egg cells of another species of goat. DNA is the chemical that carries the structure of a living thing. After an electric shock, the cells began to form embryos × embryo ROBERT PICKETT—GETTY IMAGES an animal in the early stages of development before being born or hatched (noun) The chicken embryo began to grow inside the egg. . Scientists then implanted the embryos into female goats. Only one of the embryos survived. But the newborn died in less than 10 minutes. So the Pyrenean ibex is the only species to have gone extinct twice.

Celia’s clone × clone GETTY IMAGES a plant or animal grown from a single body cell of its parent and having the same genes (noun) The scientists created a clone of a sheep. was short-lived. But it “showed that de-extinction is technically possible,” Helen Pilcher told TFK. She is a biologist and author. Since then, researchers have developed new technologies for restoring extinct species.

In Australia, scientist Michael Archer is using advanced tools to bring back the gastric-brooding frog. The amphibian went extinct in 1985. It was killed off by a disease spread by humans. Archer believes people have a responsibility to restore animals that have vanished because of human activity. His team has already produced embryos that contain the extinct frog’s DNA.

The GASTRIC- BROODING FROG gives birth through its mouth. Scientists in Australia are using frozen DNA to clone this amphibian.

The Mammophant in the Room

Scientists have had some success bringing back recently extinct animals. But it has been more challenging to restore long-dead species. That is because DNA decays over time.

Enter the woolly mammoth. These beasts disappeared from the Arctic about 4,000 years ago. Researchers have discovered their remains. But “mammoth DNA found in the wild is highly [damaged],” George Church says. He is a biologist at Harvard University.

Church uses a tool called CRISPR. With it, he inserts DNA from a mammoth into the DNA of an Asian elephant. The result will be a mammophant. It will look like an elephant but will have mammoth-like features. These will include thick hair and blood that can tolerate cold weather.

The PASSENGER PIGEON once crowded North American skies. Now scientists in the U.S. are editing the DNA of a related bird to bring back the extinct pigeon.

Church’s goal is to release mammophants into the Arctic. His plans would also protect the endangered Asian elephant. It would gain traits needed to live in such a cold region. There, the species would have a better chance of survival because it would be isolated from humans.

Restoring vanished species is within reach. But some experts say it could hurt endangered animals. “De-extinction is a damaging waste of time and resources,” Paul Ehrlich says. He is a biologist at Stanford University.

Other researchers, like Pilcher, argue that de-extinction science can help endangered animals. “It’s not a case of if de-extinction will happen,” she says, “but when.”

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