What could be more thrilling than cloning dinosaurs and letting them roam free on an island? And yet, Jurassic Park showed how doing so could also have terrifying results!
Did you know? According to TIME Magazine, an Australian project aimed at resurrecting the gastric brooding frog—extinct since 1983—was one of the 25 best inventions of 2013.
Some twenty years after the book that inspired the Jurassic Park movie was published, scientists now actually have the ability to bring extinct species back to life. Species that became extinct within the last few thousand years could be candidates for de-extinction, as long as some of their cells or traces of their DNA have been preserved. But is it really a good idea to have dodo birds, sabre-toothed cats, and woolly mammoths roaming the Earth again?
If intact cells are available, scientists could use somatic nuclear cell transfer (SNCT), the same method used to create Dolly the sheep, the first cloned mammal. The nucleus of an egg from a still-living species (such as an elephant) would be replaced with the nucleus from a cell of a closely related but extinct species (such as a woolly mammoth), effectively swapping one animal’s genetic material for another. An electrical pulse would cause the cell to start multiplying and, if all goes well, an embryo would develop. The embryo would then be implanted in a surrogate mother from the same species that provided the egg.
However, finding intact cells from extinct species is rare. More frequently, DNA fragments from extinct species are kept frozen in the permafrost or preserved in museums. These pieces of DNA can help to reconstruct the genome (genetic blueprint) of an extinct species. The genes responsible for extinct traits could then be synthesized in the lab, and gradually spliced into the genome of a living close relative through genetic engineering.
Did you know? An online poll conducted by The Huffington Post in 2013 showed that most readers were in favor of reviving extinct species.
The first attempt at de-extinction was made in 2003, when scientists used preserved cells to clone a Pyrenean ibex, a species of wild goat that became extinct in January 2000. They succeeded, but the clone died very shortly after birth due to a defective lung. In fact, Dolly suffered the same fate, probably because of wear and tear on the cloned DNA.
Any DNA taken from adult cells bears some marks of ageing, and, regardless of how carefully it is done, the manipulation of DNA during the cloning process leaves additional scars. As a result, clones remain hard to produce, tend to suffer from poor health, and usually live short lives.
However, recent advances in stem cell technologies could soon eliminate problems related to DNA damage. By bringing adult cells back to germ cell stage (before these cells develop into egg or sperm) scientists can effectively rejuvenate DNA and heal age-related scarring. This technique would also make the transfer to another egg cell unnecessary. This holds huge promise for cloning!
But is de-extinction a good idea? Some say there is a moral duty to bring back species that became extinct because of human activity, such as hunting, habitat destruction, and spreading diseases. Examples include passenger pigeons, Steller’s sea cows, and dodo birds. De-extinction would also increase biodiversity, which could benefit ecosystems. For example, big grazers like woolly mammoths would raise the quality of the soil, which could turn barren parts of the Siberian tundra back into rich grassland. Furthermore, pursuing research on de-extinction could expand knowledge of the natural world and even help save currently endangered species.
Did you know? Bringing extinct species back to life through cloning or other means has been called de-extinction, resurrection biology, and species revivalism.
Opponents argue that de-extinction efforts could take resources away from urgent conservation efforts, putting even more species at risk of extinction. Also, reintroducing a handful of individuals from an extinct species is rather pointless if they have little chance of surviving in the wild. For example, their old habitat might be gone, there would be very little genetic diversity in the population, and they would face new infections. Any of these problems could wipe them out in virtually no time.
Furthermore, reintroducing long-extinct species could easily throw the present-day natural world out of balance. For example, existing species would lack any defence mechanisms when they faced new predators. Also, a reintroduced species could become a host for a pathogen that is lethal to other, related species.
At this point, it’s not at all clear who will win the debate, and where research into de-extinction will lead. Clearly, difficult decisions will need to be made. What would you do?