The question of whether we can bring dinosaurs back to life has been addressed at the crossroads between science and pop culture countless times, from Hollywood to lecture halls by way of laboratories.
T-Rex and his dinosaur cohorts roamed the Earth about 243 million years ago, surviving the Triassic period and dominating planet-wide throughout the Jurassic and Cretaceous periods.
We Homo sapiens trailed after them. By the time our own species started making its mark on Earth some 315,000 years ago, land dinosaurs had long been wiped out by a massive asteroid which brought with it a prolonged impact winter.
The asteroid which caused the Cretaceous–Paleogene extinction event 66 million years ago was so big it would take a fast walker almost two hours to traverse its mass. It wiped out an estimated 75 per cent of species on Earth, including the non-avian dinosaurs, the largest land animals of all time.
Most of us will only encounter these incredible reptiles – Stegosaurus, Velociraptors, Triceratops, and Diplodocus, to name but a few – on the silver screen, as reimagined by Hollywood directors, or perhaps on the beaches of the Jurassic coastal areas, where their fossilised remains are scattered across the landscape.
But, one dinosaur lineage has survived to this day: birds, a kind of modern feathered dinosaur, evolved from earlier lizard-hipped dinosaurs with hollow bones and three-toed limbs during the late Jurassic period, reverse genetic engineering demonstrates.
Now, the development of a process of ‘de-extinction’ could change our relationship with entire species lost to the sands of time. Enter: the extinct woolly mammoth.
Dr Beth Shapiro, a pioneer in ‘ancient DNA’ technologies and genetic rescue, has spent decades developing the science necessary to bring extinct species back to life, so to speak, at University of California, Santa Cruz.
Speaking to UNILAD, Shapiro said she hopes the technologies necessary ‘in order for de-extinction to be a real thing’ will have ‘far-reaching application in conservation’ at a time when so many species – from the white rhino to the coral reefs – are under threat.
Using some of the keystone principles of cloning technology which brought us Dolly the sheep in 1996, Shapiro and her team figured out how to resurrect an animal a lot like the woolly mammoth, a species whose numbers began to decline around 40,000 years ago during the last ice age, before being completely wiped out by a global warming event.
Gone but not forgotten by biologists like Shapiro, who see the past ‘as a completed evolutionary experiment’ by which to learn about global biodiversity, woolly mammoth remains can be uncovered across the Siberian region of Beringia.
Some are mummified and so perfectly preserved in the permafrost, they even have intact organs lurking underneath their iconic outer layers. From these ice cold, rock hard remains, Shapiro can extract ancient DNA.
Crucially, there are no living cells in any of the mammoth remains. They’re simply too old and have been subjected to too many years of decay, so traditional cloning methods used on the likes of Dolly won’t cut the mustard.
But the woolly mammoth’s distinctive traits and characteristics and behaviours could, in principle, be seen roaming the 21st century landscape, yet.
For example, an Asian elephant already shares 99 per cent of its genome with a mammoth. So, Shapiro laughs, all scientists need to do to slowly engineer an Asian elephant to act and look just like a mammoth is to identify the remaining one per cent, and ‘cut and stick’ the two species’ divergent genomes.
A mammoth task, you might say.
In short, scientists can sequence the genome from ancient remains and the genome of a living relative; compare the two genomes to see where they’re different; and edit the genome of a living cell of a living relative so it contains the sequence of the dead relative.
In other very over-simplified words, you can put the synthesised genome of a mammoth which makes it hairy in place of the genome of a living Asian elephant which makes it not hairy through cell manipulation in a laboratory.
Doing this across the board with all the subtle differences between the long-extinct mammoth species and the living Asian elephant species will, in theory, resurrect the woolly mammoth.
Or at least something which looks and acts a lot like a woolly mammoth.
Shapiro does an incredible job – maybe more miraculous than the potential resurrection process itself – of explaining the highly-complex science simply in this talk at the Royal Institution:
Although Shapiro doesn’t make a habit of bringing extinct species back to life, the practice has received a lot of media attention and is shrouded by some controversy from corners of society who think science should leave well alone.
However, de-extinction and genetic rescue isn’t just a power trip for people ‘playing God’.
Supporters, such as Revive&Restore, an organisation facilitating de-extinction efforts on heath hens, black-footed ferret genetic rescue, and peregrine falcon genomics, hope this technology can be used to help endangered species.
Indeed, it is hoped the traits and characteristics of passenger pigeons – an extinct species of bird which populated North America – can be resurrected to protect the other animals who once shared its habitat.
Ben Novak, who is leading The Great Passenger Pigeon Comeback, told UNILAD the mission to bring this eerily-named necrofauna back to life is important to ‘restore their ecological role’, without which many forests and inhabitants in America are at risk.
Before passenger pigeons were hunted to extinction by people who orchestrated ‘industrial scale harvest’ in the late 1800s, they were the ‘chief ecosystem engineers’ of east American forests for tens of thousands of years.
Their habits made way for more diverse flora and fauna to flourish in the open canopied forests of yore.
The author of Deciphering The Ecological Impact Of The Passenger Pigeon: A Synthesis Of Paleogenetics, Paleoecology, Morphology, And Physiology said:
The large dense flocks of pigeons were sustaining the regeneration cycles through their nomadic migrations over the landscape.
[They went] from one roost to another every few weeks creating major disturbances by overcrowding on tree branches and breaking them off trees, allowing sunlight to reach the forest floor which was newly covered in fertilising guano.
Today most of the forests of eastern America are closed canopy, because disturbances are rare, he laments, adding many species of plants and animals are declining due to the disappearance of the passenger pigeon.
These birds were one of the first casualties of the sixth mass extinction, which Novak says has followed in humanity’s wake as people expand around the globe, due to hunting, human-spread invasive species, disease, and habitat destruction.
Shapiro and Novak share the same overarching goal in their work: They will do what they can to help overturn the damage caused by human influence on the species – plants and animals alike – surrounding us.
Shapiro says genetic rescue, in particular, can resurrect, revive and restore living but vulnerable ecosystems and species on the verge of collapse and extinction due to unnatural factors.
Synthetic biology and genome editing, she explains, might help corals survive if they can be edited to be more resistant to heat, for example.
Other species might be edited to make them resistant to disease, too. In that sense, de-extinction and genetic rescue lets us off the hook for the damage we humans have done as a species.
The science of de-extinction, as the media dubbed it, is a controversial topic for some. Even Shapiro and Novak – as well as other prominent geneticists – continually question its use as part of their research.
Shapiro’s research has led her to suggest a seven-step method to decipher if de-extinction is possible and ethical on a case-by-case basis, with some species presenting technical and ecological challenges.
First, a good reason we want a species or proxy back must be identified – like the important ecological niche the passenger pigeon left vacant upon extinction – as well as the reason they went extinct, so a second wipeout can be avoided.
But the thing is, like it or not, extinction is a very natural part of life and evolution. It’s the product of survival of the fittest, and the building blocks of successful evolution on earth.
Indeed human dominance is only possible because the extinction of dinosaurs made space for mammals to diversify, writes Shapiro, in her best-selling book How To Clone A Mammoth: The Science of De-Extinction.
But we fear extinction because of missed opportunity: what if an animal held the cure for cancer or cleaning our oceans?
Moreover, we need to learn how to be better stewards of the planet, she adds, stressing the importance of protecting both the parts we live in and the parts that we don’t.
This can only be bettered by an understanding of genetic biodiversity, ever-changing populations and how they’re impacted by the human collective footprint. These new genetic rescue and de-extinction technologies can help.
However, Shapiro isn’t suggesting they should replace existing conservation approaches:
We need to understand the limits and potential of genetic modification as a tool for biodiversity conservation.
This technology, if applied to helping living species stay alive and to restoring present-day ecosystems, is but one of many approaches to preserving biodiversity.
We need to conserve resources, protect land and water, stop pollution and the spread of invasive species, and become more conscientious gardeners of the planet.
But we shouldn’t reject strategies like translocations and genetic rescue just because they are frightening.
Yes, there is obviously risk involved with adopting these strategies, as there is with any new technology. But there is far greater risk in not doing more than we’re doing right now.
What we’re doing now is great – but it is not enough.
So to Jurassic Park. Evidently Shapiro and Novak share little commonality with Richard Attenborough’s fictitious Dr. John Hammond, whose vision led to the creation of genetically-engineered theme park monsters.
Moreover, non-avian dinosaur bones are so old they’ve long been transformed into rocks which hold none of the DNA needed to clone an animal.
The oldest DNA that has been recovered is only about 700,000 years old and it came from from a horse bone, not a rock, which was frozen in the permafrost in the Klondike near Dawson City, Canada, in case you were wondering.
Shapiro has also been known to point out the famed amber from which the Jurassic Park characters extract insect DNA is actually a very bad preserver of anything much at all, and the frogs with which the team try to spawn dinosaurs are actually much less closely-related to the ancient reptilian overlords than birds, for example.
However, Novak, a specialist in ornithology confirmed, ‘In theory, any extant bird species could be used to give rise to dinosaurian traits’.
All birds begin embryonic development with more reptilian traits – something that has lead scientists to explore “retro-engineering” mesozoic dinosaurs for over a decade with major discoveries made to date.
For example, he continues, scientists have found mutations which created chicken embryos with reptilian snouts instead of beaks, alligator-like teeth, and ankles similar to the carnivorous two-legged dinosaurs of your childhood nightmares.
Additionally, as with the Asian elephant, scientists are familiar with the genetic makeup of chickens.
As the genes involved in feather development are known, a team of researchers could remove them and hatch a chicken with simple feathers, ‘much like the fossil dinosaurs found with primitive quill feathers’.
One could imagine combining the reptilian snout with teeth and the ankle, preventing tail resorption and hand modification, and the bird which would hatch would be the spitting image of any number of mesozoic theropods.
Essentially, from that point, one could use any number of gene editing modifications or selective breeding to produce a variety of mesozoic dinosaurian traits.
For now, though, the imagination of the award-winning director Steven Spielberg and Michael Crichton, who wrote the original cautionary tale in 1990, far outpaces the science fact Shapiro, Novak and others like them are working toward.
But with developments and safeguards that might change.
When people ask whether Shapiro thinks de-extinction will ever actually happen, she tells people it depends what we are willing to accept as a success.
Shapiro, who is currently writing a new book titled Wild(fish) Life, told UNILAD it’s important to remember this: Even if humans can create an identical genetic clone of an animal, organisms are so much more than the sequence of their DNA.
Organisms are what they are because of the combination of their DNA and the environment in which they develop – both before and after birth. Because these environments are extinct, so will remain the species.
An elephant with a few woolly mammoth genes inserted which maybe makes it hairier or gives it thicker layers of fat? That will probably eventually happen, if some of the technical and ethical hurdles can be surmounted.
But an actual 100 per cent mammoth, with mammoth gut microbes, raised by mammoths, in the ice age habitat of Beringia? Probably never.
So, there you have it. Don’t believe anything you see on the silver screen, until science catches up and blows your mind with its potential power.
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