Colossal Biosciences created a genetically modified “woolly mouse” as a step toward the goal of eventually resurrecting mammoths and other extinct animals.
A few of the woolly mouse’s notable mammoth-like features are its curly whiskers and wavy, light brown hair that grows three times longer than that of an ordinary lab mouse. Colossal said its woolly mouse could empower scientists to test theories about the link between specific DNA sequences and physical traits that allowed the mammoth to survive in cold climates.
“It is an important step toward validating our approach to resurrecting traits that have been lost to extinction and that our goal is to restore,” said Dr. Beth Shapiro, chief science officer at Colossal, in a news release Tuesday. Shapiro is currently on a leave of absence from her role as professor of ecology and evolutionary biology at the University of California, Santa Cruz.
The team began the process of creating the woolly mouse by identifying genetic variants where mammoths differed from their closest living relative, the Asian elephant. They located 10 variants relating to hair thickness, length, texture, color, and body fat that correlated with known DNA variants in lab mice.
For example, according to a news release, scientists targeted a gene called FGF5 (fibroblast growth factor 5), which influences the cycle of hair growth to create longer, shaggy hair. They also targeted three genes related to hair follicle development to create woolly hair texture and curled whiskers and the MC1R gene, which regulates melanin production, to produce mice with golden hair.
Researchers behind the project made a total of eight edits simultaneously, utilizing three innovative techniques, to seven mice genes.
“I think that the ability to edit multiple genes at the same time in mice, and to do so and obtain the expected woolly appearance, is a very important step,” said Love Dalén, a professor of evolutionary genomics at Stockholm University and coauthor on the preprint paper. “It is a proof-of-principle that Colossal has the know-how to do this kind of gene editing, including to insert mammoth gene variants into a different species.”
The firm believes that having mammoth-like creatures in the modern Arctic would also have some environmental benefits. For example, large creatures like mammoths could compress the snow and grass that insulates the ground as they move, slowing the rate of permafrost thaw and the release of carbon.
Colossal has plans to recreate not only the woolly mammoth but also the dodo and Tasmanian tiger, or thylacine. The company has previously said it’s on track to introduce the first woolly mammoth calves in 2028.
