A few decades ago, the idea of de-extinction was just a fantasy. But science is trying to turn the idea of bringing extinct species back from fiction into reality. Scientists have identified several potential candidates, or species, for de-extinction. Cloning, DNA fusion, and other methods are used to resurrect these species. Here is a list of ten such extinct species that could be brought back to life.
1. Woolly mammoth
There is now a possibility of reviving the woolly mammoth, as scientists are trying to create a hybrid embryo that would be programmed with mammoth traits and then implanted into an Asian elephant.
The woolly mammoth inhabited Europe, Asia, Africa, and North America during the last Ice Age. It disappeared from the face of the Earth about 4,000 years ago, but the discovery of well-preserved mammoth remains has raised hopes for its revival. Scientists are attempting to bring the mammoth back through two different methods: cloning and DNA crossbreeding.
A sample found in Siberian ice remained frozen for over a millennium. Scientists are attempting to extract DNA from this sample. The DNA will then be injected into an elephant egg, which will trigger the development of a mammoth embryo. The embryo will then be implanted into the elephant's uterus. (1,2)
2. Pyrenean ibex
The Pyrenean ibex was the first animal to be made extinct by cloning, but the clone only lived for seven minutes. Efforts are currently underway to recreate the species through cloning.
The Pyrenean ibex was abundant in the Middle Ages. But overhunting in the 19th and 20th centuries led to its extinction. In 1999, the last female Pyrenean ibex was captured by scientists. They took a tissue sample from her ear, collared her, and then released her back into the wild. She lived there until 2000, when she was found dead, crushed under a tree. In 2003, scientists used the tissue sample to attempt cloning her. However, the cloned ibex calf was born with a lung defect and died just seven minutes after birth.
In late 2013, scientists announced they would attempt to recreate the Pyrenean ibex again. The new cloned ibex would be female, and since no male exists, reproduction would be impossible. A possible solution is to crossbreed such a cloned female with the closely related Southeastern Spanish ibex. This would create a hybrid animal that would ultimately be more similar to the Pyrenean ibex than to the Southeastern Spanish ibex. (1,2)
3. Woolly Rhinoceros
Scientists are trying to extract DNA from the remains of a 10,000-year-old woolly rhinoceros calf and then revive the species through crossbreeding.
Woolly rhinoceroses became extinct approximately 10,000 years ago. Since the 18th century, only a few adult woolly rhinoceros remains have been discovered. However, the remains of a baby woolly rhinoceros were recently found frozen in blood.
river bank in Siberia.
Researchers are attempting to obtain DNA from the mummy of this calf. If successful, scientists will be able to identify the rhino's closest relatives. Once the closest relative is identified, crossbreeding can be performed to produce woolly specimens.
Rhinos can be resurrected. (1,2)
4. Tours
Aurochs became extinct about 10,000 years ago, but scientists are trying to revive them using genes found in modern cattle.
Before their extinction, bison roamed the lands of Asia and Europe. They were even depicted by cavemen in striking cave paintings in Lascaux, France, dating back 17,000 years. Scientists have identified "primitive" cattle breeds that share characteristics of their bison ancestors. Thanks to these recent discoveries, these large animals may once again roam the Earth.
In 2009, a backcross program was launched between seven cattle varieties. According to Ronald Godery, the program's director, the second-generation animals have almost the same coloring as the original aurochs. They also share some other similar characteristics, such as a stripe running along the spine and long legs. Scientists claim that within six to seven generations, they will be able to create a stable group of cattle resembling the aurochs. (1,2,3)
5. Siberian cave lion
After the discovery of two frozen Siberian cave lion cubs, scientists are trying to clone them in an effort to revive the extinct species.
The Siberian cave lion descended from an earlier species, Panthera leo fossilis, which first appeared in Europe around 700,000 years ago. It became extinct approximately 12,400 years ago (according to radiocarbon dating).
In 2015, the mummified bodies of two Siberian cave lions were discovered. The cubs' bodies were so well preserved that their fur, ears, soft tissue, and even whiskers remained intact. Hwang Woo-suk, a South Korean scientist and cloning expert, collected samples from the cubs for cell research. The samples are being examined for the presence of living cells suitable for cloning. (source)
6. Quagga
The quagga, a relative of the modern zebra that went extinct more than 100 years ago, is being restored through selective breeding by a group known as the Quagga Project.
The quagga, a relative of modern zebras, went extinct over 100 years ago. But thanks to a group of scientists near Cape Town, they may soon begin roaming the Earth again. This group is called the Quagga Project.
A study of quagga skin revealed that it was a subspecies of plains zebra. Scientists believe that genes characteristic of quaggas are also present in modern zebras. Therefore, it is possible that these genes were combined through selective breeding. The resulting animals "may not be genetically identical," but they will resemble quaggas, at least in appearance. (source)
7. Thylacine
In 2008, scientists succeeded in reconstructing the genes of a Tasmanian tiger from a preserved 100-year-old specimen, paving the way for the extinct species to be reintroduced.
The first Tasmanian tiger cloning project began in 1999 at the Australian Museum in Sydney. The goal was to use genetic material obtained from specimens collected in the early 20th century to clone new individuals. In late 2002, researchers achieved some success, extracting reproducible DNA from the samples. However, on February 15, 2005, the project was halted due to severe degradation of the extracted DNA. The project was resumed in May 2005.
In 2008, researchers from the University of Melbourne and the University of Texas at Austin made significant progress in restoring the functionality of these genes. The genetic material proved functional in transgenic mice. This research raised hopes for the possible restoration of the Tasmanian tiger population. (source)
8. A frog carrying eggs in its stomach
An extinct gastric frog, which carries its eggs in its stomach, is being revived using a cloning process called somatic cell nuclear transfer.
The stomachbrooding frog was a unique species of frog that gave birth to its young through its mouth. The species became extinct in the mid-1980s. However, efforts are underway to revive the species using the somatic cell nuclear transfer (SCNT) cloning technique. In March 2013, scientists from the University of Newcastle in Australia successfully created a living embryo from the non-living, conserved genetic material of the stomachbrooding frog. (source)
9. Steppe bison
In August 2016, the tail remains of an ancient steppe bison were discovered in Siberian permafrost. Scientists are attempting to extract DNA from the tail to use it to clone the species.
The steppe bison is an extinct species of bison that once inhabited the Earth's most extensive biome—the mammoth steppe. Recently, Russian and South Korean scientists joined forces on a project to revive it. They plan to extract DNA from the tail of an 8,000-year-old bison found in the permafrost of Siberia. The tail remains were discovered in August 2016 in the Sakha Republic.
Researchers are currently attempting to clone the Canadian wood bison using a cow as a surrogate mother. If successful, it would represent a major step forward in further research on the steppe bison. (1,2,3)
10. Irish Elks
The Irish elk, which became extinct around 8,000 years ago, is now being considered by the Long Now Foundation as a potential candidate for restoration.
The Irish elk, or giant elk, is an extinct species of deer, one of the largest to ever live on Earth. It stood up to two meters tall, with an antler span of three meters. Previously thought to inhabit only Europe, its fossilized remains have also been discovered in Siberia. Scientists are compiling data on the remains of this giant elk to gain clues regarding its evolution. Research has shown that it may be closely related to the red deer or fallow deer. It is currently on the list of animals whose reintroduction to the wild is possible. (1,2,3)