The Science Corner: No, Scientists Have NOT Resurrected the Dire Wolf

I had a completely different article planned for this week, but that was before my social media feed blew up with article after article, many of which were from reputable news sources, claiming that scientists at Colossal Biosciences, a Biotech firm based in Dallas, had brought the Dire Wolf back from extinction. On April 7, Time Magazine published an article with the headline “Extinct” marked through with a red highlighter, a white wolf, and the tagline stating “This is Remus. He’s a dire wolf. The first to exist in over 10,000 years. Endangered species could be changed forever.” This colossal claim (see what I did there) is at best highly misleading - I’d go so far as to describe it, from a biological standpoint, as “fake news”.

First off, what was the Dire Wolf? The Dire Wolf, scientifically known as Aenocyon dirus, was part of the Pleistocene megafauna that inhabited North America up until about the end of the last Ice Age, about 10,000 years ago. It lived side-by-side with both the early indigenous human populations of North America AND with the Wolf, Canis lupus. The Dire Wolf was less closely related to wolves than are India’s Dhole, Cuon alpinus or the African Hunting Dogs, Lycaon pictus (among other species). It was not simply a “big wolf” or a “super wolf”, but a large member of the Canid (dog) family tree that had powerful jaws and forelegs, presumably adaptations for hunting the large extinct bison and other members of the Pleistocene megafauna. Dire Wolf skeletons and remains are plentiful from Los Angeles’ La Brea Tar Pit deposits, and they have been found across much of temperate North America. In comparison to modern surviving wolves, they weren’t much larger, in fact. The largest Gray Wolf subspecies averaged around 132 pounds, while the largest Dire Wolves are estimated to have averaged around 150 pounds. BUT they were not “wolves” - this is a case of common names being misleading about actual relationships between species (as an aside, most high school biology classes do a lesson on this very subject when teaching about scientific names vs common names - one reason to NOT use common names is that they are frequently misleading about the actual relationships between groups). Since this common name is misleading, for the rest of this article I’ll put “Wolf” in quotations when discussing the Dire “Wolf”.

Fictional representations of Dire “Wolves” are also typically inaccurate - for example, the Dire “Wolves” on Game of Thrones are depicted as nothing more than giant Gray Wolves, one of which happened to be white. Given that Dire “Wolf” remains were associated primarily with savanna rather than arctic habitats, & unlikely that any of them were actually white, unless they were lacking pigment due to genetic anomaly. In all likelihood, the Dire “Wolf” was some shade of tan or brown, likely mottled and grizzled as are many other wild canids (but that is speculation based on habitat association and informed by living canid species - we really can’t know for sure).

So what did Colossal Biosciences do? Long story short, they made a GMO wolf. They then made the claim that “if it looks like a duck, and quacks like a duck, then it must be a duck”. With the “duck” being a “Dire Wolf”. In detail, they looked at a recovered partial genome extracted from a tooth and other fossil remains of a couple of Dire “Wolf” fossils and sequenced some of the genes. Then they used a gene-editing technique called CRISPR to rewrite 20 Gray Wolf genes in order to increase the size, musculature, and coat color of the Gray Wolf and inserted those genes into the genome of a wolf nucleus - no actual Dire “Wolf” genes were used. They then used techniques established 25+ years ago in cloning livestock (see “Dolly the Sheep”) to replace the nucleus in a domestic dog egg cell with the genetically modified wolf nucleus, stimulated that egg to grow and develop as an embryo, then implanted that modified embryo into the uterus of a dog. A couple of months later, that dog gave birth to the GMO “Dire Wolf” puppies (there are 3 of them at this time). Although Wolves, Dogs, and Dire “Wolves” do share a significant amount of genetic material (95+%), 20 genes is still a fraction of the difference between these species (most mammals have in excess of 20,000 different protein-coding genes).

Colossal biosciences then went on to claim that while its true that under a “phylogenetic species concept” that Wolves and Dire “Wolves” aren’t very closely related but that they instead preferred a “morphological species concept” and that their GMO Wolves were functionally the same as Dire “Wolves” so that they should be called Dire “Wolves”. While in evolutionary biology, there is an ongoing debate about what exactly species are, and which species concept best describes them - their description of the morphological species concept is inaccurate. Most biologists are proponents of either an evolutionary (ancestor-descendant lineage-based) species concept or a biological (populations can interbreed with each other) species concept - these variously describe species based on characteristics inherent in populations, with different emphases on different characteristics. The actual morphological species concept was used primarily prior to 1900, and it described species based on their physical characteristics measured from actual specimens only. A combination of morphology and lineage-based species concepts remains the only way to classify extinct species (you can’t assess “interbreeding” between populations that are extinct). However, under a morphological species concept, specimens have to match in a wide array of (usually) skeletal details. Even if you were to stretch the morphological species concept to include “functional morphology”, it is unlikely that these GMO wolves are remotely “functionally the same” as the extinct Dire “Wolf”. So, even under the morphological species concept, the Colossal Biotech “Dire Wolves” don’t measure up - they are emphatically Gray Wolves, that only resemble fictional depictions of “Dire Wolves” - notably, Jon Snow’s “direwolf” Ghost from Game of Thrones!