The scientists then rewrote the 14 key genes in the cell’s nucleus to match those of the dire wolf; no ancient dire wolf DNA was actually spliced into the gray wolf’s genome.

Whether the existing dire wolves or others Colossal might produce will be allowed to mate and spawn a next generation of wolves naturally is not yet known. Handlers can monitor the female estrous cycles and separate the animals at key times or employ contraceptive implants that keep the wolves from producing young until it is determined whether they have any abnormalities that could be passed on.