Photo by Natural, CC BY 4.0 on GoodFon

By: Madison Fung

Dire wolves, a canine species once native to North America and parts of western South America, have been extinct for over 10,000 years. Despite the close resemblance in appearance, dire wolves have a distinct genetic lineage from modern grey wolves. There is currently no evidence of interbreeding between these two species. Upon careful examination, the characteristics of dire wolves were found to be rather different from those of grey wolves, with features such as a larger skull and smaller brain.

In an attempt to resurrect the existence of dire wolves, biotechnology company Colossal Biosciences successfully created three pups bearing the DNA signatures of dire wolves: Romulus, Remus and Khaleesi. 

Colossal scientists deciphered the dire wolf genome by analysing ancient DNA from a 13,000-year-old tooth and a 72,000-year-old skull of fossilised dire wolf remains. The scientists discovered around 20 genetic differences in 14 genes by comparing the genome of the dire wolf to that of the modern grey wolf. With the help of CRISPR-Cas9, a gene-editing system, the modern grey wolf genome was edited to match the genetic code of the dire wolf. Embryos with modified cells were implanted into surrogate domestic dogs, giving birth to Romulus and Remus in October, and Khaleesi in January.

Although the pups have the physical traits of dire wolves, the topic of de-extinction remains controversial. Various experts argue that Colossal has not recreated dire wolves from extinction, with zoologist Philip Seddon from the University of Otago claiming that the pups are simply “genetically modified grey wolves”.

“So what Colossal has produced is a grey wolf, but it has some dire wolf-like characteristics, like a larger skull and white fur,” Paleogeneticist Dr Nic Rawlence says.

On the other hand, the project still demonstrates the advancement of synthetic biology and serves as a milestone for genetic engineering. The development of techniques, including DNA extraction and genetic sequencing, has potential in the conservation of endangered species.

Works Cited

“Dire wolf | Size, Origins, De-Extinction, & Characteristics.” Britannica, 14 April 2025, https://www.britannica.com/animal/dire-wolf. Accessed 21 April 2025.

Gill, Victoria. “Experts dispute Colossal claim dire wolf back from extinction.” BBC, 8 April 2025, https://www.bbc.com/news/articles/c4g9ejy3gdvo. Accessed 21 April 2025.

Hearn, Timothy. “’Return’ of the dire wolf is an impressive feat of genetic engineering, not a reversal of extinction.” The Conversation, 8 April 2025, https://theconversation.com/return-of-the-dire-wolf-is-an-impressive-feat-of-genetic-engineering-not-a-reversal-of-extinction-254098. Accessed 21 April 2025.

Kluger, Jeffrey. “The Return of the Dire Wolf | TIME.” Time, 7 April 2025, https://time.com/7274542/colossal-dire-wolf/. Accessed 21 April 2025.Kluger, Jeffrey. “The Science Behind the Return of the Dire Wolf.” Time, 7 April 2025, https://time.com/7275439/science-behind-dire-wolf-return/. Accessed 21 April 2025.