The study of the dire wolf genome has enabled the Colossal team to identify distinctive features that set the ancient wolf apart from its modern relatives. These characteristics include size, musculature, hair color, hair texture, hair length, and coat patterning. Using gene editing, the team modified the genome of cells from the dire wolf’s closest living relative, the gray wolf. In total, the company conducted 20 unique edits to 14 genes in the gray wolf genome, with 15 of these edits intended to reproduce extinct dire wolf gene variants. Colossal claims this is a record number of unique genetic edits performed on any animal.
Despite these modifications, the dire wolf genome remains almost identical to that of the gray wolf, raising questions about whether these animals are truly dire wolves or simply gene-edited gray wolves. Ben Lamm insists that the animals are dire wolves, stating, “We call them dire wolves.” The concept of speciation often incorporates both genetic and observable physical characteristics, including aspects such as teeth and body shape, size, and color.
George Church, a Harvard University genetics professor and cofounder of the company with Lamm, mentions that the ultimate goal is to create an animal with the complete genome of an extinct dire wolf. “In the meantime, we’re prioritizing all the traits that actually define the species,” he asserts.
Beth Shapiro also believes the genetic edits are substantial enough to classify the new animals as dire wolves, stating, “If we can look at this animal and see what it’s doing, and it looks like a dire wolf and acts like a dire wolf, I’m going to call it a dire wolf.” Despite some taxonomists potentially disagreeing.
David Jachowski, a professor of conservation at Clemson University, suggests there is “inherently some subjectivity” in defining species. He notes that an animal’s role in its ecosystem can be as crucial as its genetic makeup, highlighting the significant marketing value in declaring a species as de-extinct for wildlife conservation.
To create the dire wolf, Colossal began with blood drawn from a gray wolf. Focusing on a type of blood cell called an epithelial progenitor cell, the team edited the DNA to more closely match the dire wolf genome. The genetic material from this cell was then inserted into the egg cell of a domestic dog, which had had its genetic material removed. After developing into an embryo, the egg cell was implanted into a surrogate dog.
It required eight surrogates and an average of 45 embryos per surrogate to produce the dire wolf pups. Two surrogates gave birth to pups named Romulus and Remus, while a third produced Khaleesi. Five of the embryo transfers did not result in successful pregnancies. Another female was born alongside Khaleesi in January but died after 10 days due to an intestinal infection.