When Jurassic Park released in 1993, moviegoers were spellbound looking at the dinosaurs brought back to ‘life on screen’. Micheal Crichton’s science fiction book had a fanciful and thrilling plot that translated into pure cinematic joy. Scientists somehow revive T-Rex and Velociraptors and all hell breaks loose. Besides entertaining the hell out of cinema lovers, the movie planted everyone with an idea. Can we bring back extinct animals from the dead?
As it turns out, we probably can. Scientists at Harvard are trying their best to revive the Wooly Mammoth (Remember Manfred “Manny” from Ice Age). Wooly Mammoths are one of the most easily recognizable extinct creatures and were wiped out in one of the five mass extinction events. And now, we can possibly see them in flesh – thanks to a revolutionary tool that can modify the code of life – DNA. This tool, CRISPR, has been making the news lately for being a means of genetic engineering that precisely modifies available DNA samples with minimum errors, enabling scientists to model and find a cure for many genetic diseases. But how is this achieved? We have broken down the process of this seemingly magical technology in the November issue of Digit and although the inner workings of this process seem sound enough, there is a nagging question that remains – where will the DNA of the “dead” animals come from?
The DNA Question
The Jurrasic Park technique of mining dinosaur DNA from fossilised mosquitoes doesn’t quite work in reality, as Dino DNA doesn’t quite survive the vagaries of age. In the case of Mammoths, being from the Ice Age comes with its own benefits. The Wooly Mammoths that went extinct during this period got buried under huge chunks of ice and snow leading to proper preservation of their tissues. One such specimen, that of a 39,000-year-old female baby mammoth was discovered in Siberia in 2010. The specimen, named Yuka has been the source of all information we need to reconstruct these species. Equipped with the power and precision of CRISPR, the DNA encoding for mammoth features is being engineered into the embryo of an Asiatic elephant to produce a hybrid – a Mammophant.
The chosen one
The reason for choosing an Asiatic elephant over its cousin – The African Elephant, for making the hybrid is that the Asiatic Elephant is genetically closer to the Mammoth, similar to how humans are more closely related to chimpanzees than to gorillas. This reduces the number of genetic changes needed. The group of scientists at Harvard have made 15 edits in the Asiatic elephant DNA and they hope to increase it to 45 edits soon to make the Mammophant as close to a mammoth as possible. With these edits in place, they then wish to grow this hybrid in an artificial womb in a laboratory. That is quite a massive task. The time taken for a mammoth/elephant embryo to grow is around 660 days, and using current state of art only mice embryos have been cultured this way, that too for only 10 days – out of which half the time they originally spend within their mother’s womb. Is there any reason why scientists want to embark on this difficult line of research – beyond the novelty factor?
The original idea of reviving creatures of the past, especially the Wooly Mammoth, is to the credit of a Russian scientist, Sergey Zimov. He envisioned the Pleistocene Park (similar to Jurassic Park but named after the Ice Age), an area where human intervention is restoring the habitat to the grassland like Mammoth Steppe, a form of cold climate African savanna. He believes that reanimating this ecosystem could potentially help prevent climate change. It was this radical idea, that convinced George Church (the leading scientist of this group at Harvard), to take up the revival of the mammoth.
Mammoth like creatures could help preventing the underground layers in tundra (permafrosts) from melting. Tundras are the highest source of carbon in the Arctic owing to their being a rich burial ground for a massive amount of flora and fauna of the past. If these melt, the sheer amount of methane released will exacerbate the damage done by carbon dioxide to the atmosphere by manifold. By punching through the snow, these huge herbivores let cold air pass over it, restoring these permafrosts to their original frozen state. During summer months when trees replace grass, they were responsible for knocking down trees, either when they sharpened their tusks/horns, indulged in a show of strength or just cleared their path. This helped in clearing the forests, which in case of the Arctic tundra is beneficial as the forest cover absorbs a lot of sunlight and heat leading to rise in temperatures. Grass, instead, does not absorb as much sunlight causing much of it to be reflected. These findings unravel how intimately the flora, fauna and climate of an ecosystem are linked and how introduction of a species like the Wooly Mammoth could be the just the element needed to sustain it.
All the problems
Though resurrection biology seems to have caught the fancy of a lot people, not all are convinced by its tall claims. Conservation biologists believe that the governments around the world should try and preserve the present day fauna. Also, even if the mammoths return, owing to their limited source DNA (obtained from only few individuals), all the mammoths will end up have identical genetic makeup. Hence, mistakes in their DNA code will get accumulated over time leading to their ultimate wipeout. Additionally, the process of generating this hybrid utilises Asiatic elephant embryos, which is a nightmare for conservation biologists as these elephants are shrinking in terms of their numbers. On the other hand, nurturing an animal ex- vivo (outside a living being) would make the baby mammoth devoid of the essential contact it harbours with its mother right from its conception. This could have serious implications, ethically as well as physiologically. Mammoths, like elephants, are highly social animals and these new-age hybrids might lack social skills owing to the absence of peers. Critics remark that the entire project would reduce to creating a miniscule amount of hybrids to be used as show ponies for wealthy individuals. Then there is this annoying thing called chaos. Chaotic systems show a sensitive dependence on variables – small changes lead to massive deviations. On paper, the reanimation of a species and subsequent reintroduction into the environment might seem straightforward, but because the number of variables that the system depends on is so huge, a small variation could throw the entire ecosystem into disarray.
A resurrection – a revival
Like any new bold science project that catches the public attention, the Wooly Mammoth resurrection project surely has its pitfalls and has attracted its share of brickbats as well has having large scale benefits. Enthusiasts of the field believe that resurrection and re-animation (restoration of animals belonging to a region) are important as they garner attention and generate resources for conservation efforts as people might be interested in funding such “cool” programmes. Mammophants would bring back useful traits into the genetic pool, in turn helping the Asiatic elephant recover from the brink of extinction by making them more resistant to habitat change.
Wooly Mammoths were prey to a the fifth mass extinction event. We are now in midst of a sixth, triggered not by natural causes but by mankind. Any experiment that can reverse the damage done to Earth by humankind is worthy and no monetary based argument should be a valid one against it. Sometimes betting on the future of science can reap rich dividends. It worked for LIGO, for the LHC. We continue pumping money to the ITER project for nuclear fusion based energy. Trying to bring back a creature from the Ice Age as a biological experiment…Why not!
With inputs from @RonakGupta
This article was first published in the April 2017 issue of Digit magazine. To read Digit’s articles first, subscribe here or download the Digit app for Android and iOS. You could also buy Digit’s previous issues here.