Life Finds A Way
Welcome to Jurassic Park! Or welcome to 2022 Australia where we are simultaneously expanding our fossil fuel projects to the equivalent of 200 new coal power stations and trying to bring back the Tasmanian Tiger (Thylacine) from extinction. Quite the paradox, isn’t it?
Big, grand ideas like de-extinction divert us from the terrors of the world and make us reminisce about happier past times – whether they’re realistic or not. Science is remarkable in that it constantly walks the uphill battle of convincing people that we ARE capable of doing the impossible. To reach the unreachable. People laughed when we dreamed of going to the moon or curing polio – until we did precisely that. A little bit of faith (and A LOT of money) can go a long way.
So, could we make our Jurassic Park dreams a reality? What if we could bring Thylacine back from the dead? How would we do it? Or, a better question… Should we? Well, hold onto your butts, because I’m about to dive into de-extinction and whether I *think* we can and should bring Thylacine back from the dead.
The Jurassic Park Method
You’re probably all quite familiar with de-extinction thanks to Jurassic Park, but there are a few different iterations and techniques involved with bringing something back from the dead. The Jurassic Park method involves extracting DNA from dinosaur blood sucked up by a mosquito (which was conveniently frozen/preserved in fossilised amber) and then combining that DNA with frog DNA to ‘fill in the gaps’, then implanting that frog/dinosaur hybrid DNA into an ostrich egg.
Sound simple? Although I love #simplescience, this is highly, highly unlikely to create a living, breathing dinosaur. Anybody experienced with DNA extraction, purification and amplification will tell you that, in reality, these processes are incredibly sensitive, and geneticists are scared to even breathe near a sample in fear of contaminating it with their own DNA (but that’s Hollywood!). So, there are definitely some limitations with what they’ve claimed, but, hey, that’s science fiction – They’re supposed to stretch what is scientifically possible, so we can’t fault them for having an imagination, but I’m going to anyway.
Firstly, the DNA that the scientists would have extracted would only be a tiny fraction of the DNA that’s inside that mosquito. Imagine how many other dinosaurs that mosquito had bitten, and how many times the blood was mixed with that of other dinosaurs or even different species of dinosaurs, not to mention the mosquito’s own DNA complicating things. Ever tried to pick out just the carrot from a bolognese? Or just the salt from a chicken soup?
It’s incredibly unlikely that the DNA is pure enough to represent a single dinosaur species reliably. But, for argument’s sake, let’s assume the DNA they extracted was pure velociraptor DNA. Why did they mix it with frog DNA? Well, enter problem number two.
To bring an animal back from the dead, you need a complete genome. However, more often than not (and in the case of Jurassic Park), the recovered/extracted DNA is incomplete or damaged. So, you can either use the DNA of the same species (ideal) or a closely related species to fill in the gaps/replace the damaged parts – but a frog? Really? How closely related are frogs to dinosaurs? Not very.
We’ve known for quite a while now that modern-day birds are actually the closest living relatives of dinosaurs. I mean, look at that cassowary – does that NOT look like a dinosaur? Dr Wu and his Jurassic Park scientists must have some rhyme and reason for using frogs instead of birds, but maybe they forgot about birds. Wait, no, they didn’t. Because after creating a dinosaur-frog hybrid, they then implanted that DNA into an ostrich egg… Why did they use frog DNA (besides apparently allowing the female dinosaurs to change sex/breed) instead of ostrich DNA? Beats me…
Anyway, coming back to this mixing of DNA. While filling in the gaps of damaged or missing DNA is a completely valid technique, the odds that the velociraptor DNA they’re playing with isn’t completely degraded after the ~80MILLION years of being stuck inside a mosquito is probably the biggest bone I have to pick with Dr Wu (we’ll leave John Hammond out of this, because you can’t be mad at the guy).
Over time, the hydrogen bonds that hold DNA bases together break down, making it very difficult to read and interpret. So, the ‘gaps’ they’re talking about are more like yearning chasms of missing/damaged DNA instead of a few potholes in the road. How do we know where the DNA that’s missing fits into the genome, and in what order? Well, without an appropriate template to compare against, we don’t. Imagine trying to piece back a book that’s been through the shredder; the pieces are there, but the order is almost impossible to figure out.
SO. Impure DNA samples, large areas of missing/damaged DNA, and inappropriate template species DNA are working in tandem to NOT bring back a velociraptor (sad face). So, a science-fiction movie is exactly that… Science fiction (no surprises there). But how does this relate to Thylacine? Could we use the same ideas from Jurassic Park with modern-day science tech to make it a reality? Possibly.
The last known living Thylacine died less than 100 years ago in 1936 in Beaumaris Zoo, Tasmania. Excessive hunting and poaching drove the already at-risk species to extinction, but other factors like urbanisation and disease may have also played a role in the iconic species’ demise. So, once again, it’s our fault that something beautiful is no longer around.
However, in evolutionary terms, 100 years is a minor blip. Thylacine’s extinction is so recent, that scientists have managed to collect quite a lot of very valuable tissue from several different animals, and kept it in pretty good condition, too.
Thylacine was also an apex predator that filled an extremely important niche in the food chain and helped provide balance and stability to the local ecosystems. Since their extinction, the habitat in Tasmania has remained relatively unchanged – meaning reintroduction may not be so farfetched and it may be able to reoccupy its niche.
So, we’ve got some well-preserved tissue, we’ve sort of got the environment for it to go back into, but do we have the tech? Not quite, but we’re well on our way to having it.
How Will We Bring Them Back?
Well, very similar to how the dinosaurs were fictitiously brought back! Find some good quality DNA, tweak it with that of a closely related species, and then transfer that DNA into a host species egg (an ostrich in Jurassic Park, more like a Tasmanian Devil for Thylacine) for it to grow and gestate – Once again, sounds simple, doesn’t it? Remember, #scienceisneverthatsimple.
A research lab at the University of Melbourne is leading the way in bringing Thylacine back from extinction and has already made some headway in defining some of those very complex protocols and techniques. Essentially, the team have broken it down into 3 broad steps: 1) Fully sequence the Thylacine genome and one of its closest relatives (in this case, that’s the fat-tailed dunnart), 2) define protocols to grow and culture Thylacine stem cells, and 3) develop the reproductive techniques like enucleating oocytes, embryo culture and transfers to put the icing on the de-extinction cake. These are all very standard laboratory techniques, but marsupials present with some extremely unique biology and hurdles to overcome when it comes to reproduction.
Thankfully, scientists have already ticked off the first step of sequencing Thylacine and dunnart genomes, and are currently working on ways to grow and culture marsupial stem cells. But, unfortunately, that is where the story ends… for now. But this gives us a chance to ponder and reflect if this is something we should be doing in the first place.
What’s the Right Choice?
I definitely don’t pretend to be an ethicist/bioethicist, and it is a lot more complicated than I, and many others, gives it credit for. But, it’s hard not to think about other research or different conservation efforts that we could be working on and funding instead of bringing back a species that we killed off. After all, “genomes don’t save species, only habitat and protection do.”
Would it not be more prudent to prevent other, extant species from going extinct instead of putting all of our extremely valuable time and resources into an immensely difficult endeavour that may not be the *right* decision for conservation/ecology? Let’s say we do bring back a Thylacine, and we get some adorable stripey babies and the world oohs and aahs over how cute they are and what an incredible achievement it is for science. Well, we’ve actually done this before in different species… And it didn’t really go down very well.
The Pyrenean Ibex was brought back from extinction about 20 years ago and, and was the first species in the world to have been de-extincted – and then, 7 minutes later, re-extincted itself again. We’ve also cloned several different animal species before. The most famous of which would be Dolly the sheep, but we’ve also cloned mice from tissue frozen for more than 16 years, and black-footed ferrets from tissue frozen for more than 35 years – genuinely incredible stuff. However, while cloning and de-extinction are similar, they are not exactly the same, and we know a HECK of a lot more about mouse genetics and biology than we do about an already-extinct Thylacine.
Let’s say we do bring Thylacine back, and they do live a long, healthy life. What do we do with one animal? To be a reproductively viable and ecologically impactful species, you need ~500-1000 individuals (or 40 generations worth), and how in the world are we going to make that many unique individuals? How long would that take, and is this really how we should approach conservation issues – Being reactive instead of proactive? If de-extinction does work, and we can bring species back from the dead, we will risk becoming ambivalent to species extinction because we can simply bring them back later, rather than fixing the environmental or societal pressures that led to their demise in the first place.
While we don’t quite have the answers yet, that’s why science and nature are so fascinating. They are in a constant state of motion: continually evolving and adjusting to deal with whatever the world has to throw at them. We may not have the answers to these complex questions now, but we will soon. After all, if there is anything evolution has taught us, it’s that life is resilient. Malleable. Sometimes, life, uh, finds a way.