~ By Aarushi Mundra
If you have ever been fascinated by the creatures in the movies 'Jurassic Park' or 'Ice Age', you would be excited to know that the revival of such extinct species is no longer a fantasy. The notion of bringing vanished species back to life has hovered at the boundary between reality and science fiction for more than two decades, ever since novelist Michael Crichton unleashed the dinosaurs of Jurassic Park on the world. It is now possible to sequence and assemble the genome of extinct organisms from highly degraded tissues and this technique enables scientists to pursue de-extinction in a wider array of species, including those for which no well-preserved remains exist.
Ecologists at the University of California, Santa Barbara (UCSB), in August 2016, published guidelines on how to choose which species to revive in order to maintain our planet's ecosystems. The two animals at the forefront of this discussion were the woolly mammoth--a hairy and close relative of the elephants that lived in the Arctic-- and the passenger pigeon-- a small, grey bird with a pinkish-red breast once extremely common in North America. The last mammoths died about 4000 years ago, while the passenger pigeons vanished in around 1900. Both the passenger pigeon and woolly mammoth were functionally unique species. Bringing back the giants could help convert the Arctic tundra back to grasslands that existed during the last ice age. Likewise, the passenger pigeons played a dramatic role in shaping the forests they inhabited.
Methods scientists adopt for de-extinction include:
Back breeding: Breeding animals that have traits similar to the extinct species in order to create a version that closely resembles it.
Cloning: The process of taking a preserved cell from a recently extinct animal, extracting the nucleus, swapping this nucleus into an egg cell from the animal’s closest living relative and finally implanting the egg into a surrogate host. Through this method, a wild goat known as bucardo or Pyrenean ibex was revived. The last of this species, nicknamed Celia, died when she was crushed beneath a fallen tree however, her cells lived on and by the method of cloning, 57 implantations were made in the next few years. Out of these, only one animal, a hybrid between Spanish ibex and a goat carried a clone of Celia to term. The infant, however, lived only 10 minutes because of genetic problems with its lungs.
Genetic engineering: Researchers in this method, line up the genome of an extinct animal with that of its closest living relative. They then use CRISPR and other gene-editing tools to swap relevant genes from the extinct animal into the living species and implant the hybrid genome into a surrogate or grow it in an artificial womb. This approach doesn’t produce genetically identical copies of extinct animals, but rather modern versions of an animal engineered to look and behave like its extinct relatives. This method is being used for the revival of mammoths and passenger pigeons.
Like every coin has two sides, the process of de-extinction comes with its cons as well.
There is a threat of new diseases with de-extinction. When an entire species goes extinct, then the diseases that impacted their health disappear from the planet. Going through the process of de-extinction could cause some of the pathogens, bacteria, or viruses to come back with them
De-extinction could cause even more species to go extinct. In a review of the key points of de-extinction for New Zealand, writer Jenna Small, noted for Science Glory that there are risks that would occur for our current species with this process”.The cost to bring back five extinct species from New South Wales could help to preserve up to 42 living species.” she writes.
Political objections: De-extinction could change priorities in other fields of science, such as medical research and the conservation of currently endangered species.
Nevertheless, critics believe that in time, extinction could be a thing of the past. De-extinction is speeding closer to reality, and now is the time to start thinking about it. Douglas McCauley, an ecologist at University of California, Santa Barbara says, “For a long time it was easy to just put it aside because the technology wasn't there but I don’t think we can do that anymore.”
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