Can fans of the popular HBO series Game of Thrones rejoice at the return of one of the series’ most iconic animals? The Dallas-based biotech company Colossal Biosciences announced that it used “deft genetic engineering and ancient DNA” to breed three dire wolf puppies and “de-extinct” the species.

Gene Editing

Dire wolf; Photo: Colossal Biosciences
Dire wolf; Photo: Colossal Biosciences

Colossal Biosciences, which is also working to de-extinct the wooly mammoth and Tasmanian tiger, is attempting to resurrect this species of wolf that roamed the Americas approximately 12,500 years ago. The new wolf pups—named Remus, Romulus, and Khaleesi—may represent a technological marvel, but are they really dire wolves?

According to Zoologist Philip Seddon from the University of Otago in New Zealand, the animals are actually  “genetically modified grey wolves”. There are distinct biological differences between Colossal Biosciences’ dire wolf and the dire wolf that existed during the Earth’s last ice age.

Paleogeneticist Dr. Nic Rawlence, also from Otago University, stated that the ancient dire wolf DNA from fossilized remains is too degraded and damaged to be copied or cloned biologically.

Rather than cloning, scientists behind the project used new synthetic biology technology and ancient DNA to identify key segments of code that could be edited into the biological blueprint of a living animal. By isolating the parts of the DNA that contained physical dire wolf traits, Colossal Biosciences was able to create an animal with a physical appearance identical to an ancient dire wolf without being genetically identical.

Dire Wolf Puppies

“So what Colossal has produced is a grey wolf, but it has some dire wolf-like characteristics, like a larger skull and white fur,” said Dr Rawlence to BBC News. “It’s a hybrid.”

Genetically edited embryos were placed in surrogate domestic dog mothers and the wolves were birthed by planned cesarean section to minimize complications. The wolf pups are currently being kept in a private 2,000-acre facility at an undisclosed location in the northern U.S.

“This massive milestone is the first of many coming examples demonstrating that our end-to-end de-extinction technology stack works,” said Ben Lamm, Colossal’s cofounder and CEO, in a news release. “Our team took DNA from a 13,000 year old tooth and a 72,000 year old skull and made healthy dire wolf puppies.”