Dire wolves are back, sort of, so what does this mean for extinct species of fish?
My two favourite movies are Jaws and Jurassic Park. It’s the latter that seemed more relevant today when Colossal Biosciences announced that they had brought Dire Wolves back from extinction. I wasn’t the only one, the comments on their social media pages included “Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should.” and “T-Rex doesn’t want to be fed. He wants to hunt. Can’t just suppress 65 million years of gut instinct.”
Despite a generation being brought up watching movies about why bringing extinct animals back to life is a bad idea, it has happened, well sort of happened. Now Romulus and Remus two adorable pups are showing off their howls on Colossal’s YouTube channels. There is a younger pup somewhere Khaleesi.
What is a dire wolf?
The dire wolf (Aenocyon dirus) lived in the Americas between 125,000 -10 000 years ago. They were one of the large predators that hunted the megafauna that was around at the time. They vanished during the quaternary extinction event. There is a huge debate as to why they vanished. But given we’re still debating why some cichlids went extinct relatively recently you can see why there is still some doubt about why these wolf-like animals vanished.
Here is the sticking point, many scientists consider dire wolves to no longer be a species of Canidae. Dire wolves and grey wolves split down different branches of the family tree 5.7 million years ago. There is some evidence that they might have crossbred some 3 million years ago, but again that is up for debate.
To put that into perspective. We split from chimps about 6 million years ago according to some studies.
How did they recreate them?
So was this a mosquito trapped in amber moment, no.
The team mapped the DNA of two dire wolf fossils. One from about 75000 years ago and one 13 000 years ago. Then they compared that to the DNA of the Grey Wolf, and identified the difference. Now we have sticking point one. There are millions of differences between a grey wolf and a dire wolf. 80 genes are distinctly different, including size, ear shape, coat colour and more.
The team identified the 20 most important differences and set out to alter the Gray Wolves’ DNA in those locations. 15 changes were made, and 5 changes were discarded as they’re known to cause issues including deafness and blindness in grey wolves.
They did find mutations to those five genes in dogs and grey wolves and used those instead.
The first two pups were born in October last year. 4 have been born in total, but one died due to a ruptured intestine. The third, Khalesi was born in January of this year.
So are they real Dire wolves?
The scientific community are pretty firm on the fact these are not Dire wolves. They are grey wolves with some gene editing to make them look like dire wolves. A novelty, and very interesting, but not the real deal. Even if you ignore all the genes that are grey wolf, and not dire wolf, they are being raised by wolves, they have none of the gut microbiome of dire wolves, and they won’t grow up hunting and eating the prey of dire wolves.
But this same technology can be useful for species that are endangered or very recently extinct.
What species of fish might we bring back?
Chinese Paddle Fish
In 2022 the Chinese Paddlefish was declared extinct. Overfishing and habitat loss meant that this huge species of fish was no longer sharing this planet with us. Growing up to 3m long, but reports of specimens up to 7m long have been recorded, with its paddle forming about a third of its body length, it spent part of its life in the ocean before migrating upriver to spawn. The building of dams along the Yangtze River, including the Gezhouba and the Three Gorges dams blocked these spawning migrations and fragmented the populations.
There aren’t any closely related species, although sturgeons will share a lot of genes. There is the American paddlefish, but there are a lot of genetic differences. But assuming we can use this new technology there are ways to bring these fish back from extinction.
But there isn’t anywhere for them to go. We could keep them in aquaria, but there are other species far more suited for that life. There is no natural habitat for them to be returned to with the dams that spelt the end for the wild populations still in place, and putting them in another river would threaten other species as these large fish came in to upset already precarious balances.
So what about other species?
Catarina pupfish
By Fishspeciation – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=99955296
In 1994 a spring-fed pool in Nuevo Leon Mexico dried out. That spring contained several species including the Catarina pupfish. Some individuals were found in side springs, and taken into captivity, but they proved to be difficult to maintain, unlike the Potosi pupfish, also found in the same pool. In 2014 the last male died and the species was declared extinct.
Pupfish are killifish, highly adapted to the harsh conditions that nature can throw at them. The Salt Creek pupfish thrives in water so salty that it would kill many species of marine fish, and Devil’s Hole pupfish are hanging on in conditions that would have caused many other species to go extinct.
As the environment changes around them these fish adapt to those conditions and specialise for that natural habitat, often in a single pool or creek.
The cost of this isolation is that if that tiny habitat vanishes, so do the species. Sadly that was the cost to the Catarina pupfish. Even without humans in the world, many species of pupfish have evolved, and been lost as nature altered their home turf.
Fundulus albolineatus (Whiteline Top Minnow)
But what about species that humans have directly contributed to the loss of? The Whiteline top minnow vanished in the late 1800s as Big Spring Madison County Alabama expanded. Again a species of killifish these are almost identical to the Barren’s topminnow, a species that is endangered in itself.
These two species present two other arguments. Both are endemic to a tiny area, and neither have a home to return to, so the only aim is to keep them in aquaria in the hope their native range reappears one day. For the Whiteline topminnow, there is an almost identical species already, one that needs the help, and funding to be saved from extinction already.
Why do we need de-extinction?
There are a lot of reasons to want to stop species from going extinct, but often we need to be saving their habitat and all the other species that are within that space. Look at the Dire Wolves, the range they once lived in is now populated by grey wolves and coyotes. There is none of the megafauna that they might have hunted. Nature has moved on and their space has been occupied.
In terms of fish so many habitats are being destroyed, and we have to be realistic. Dams are being built, pollution is being spilled, and forests chopped down. Rather than gene editing one fish to look like another we need to be conserving the environment where they live. Creating conditions in the hope that residual populations still exist and they can bounce back.
My concern is that conservation efforts might be hampered by this news. The average person won’t want to save a key species and its habitat, assuming that once it goes extinct it can be brought back through dextinction. But saving one species and its habitat can save thousands of other species that are living alongside them.
Maybe in the distant future, we can have a record of these DNA maps. Maybe one day you’ll be able to 3D print the eggs of a long-extinct species. I wonder, will that be on Earth or after we’ve started to settle on other planets?
Which species would you want to record, and what would you want to bring back from the red list of extinct species?
