De-extinction startup Colossal Biosciences has gene-edited mice to have mammoth-like features, creating what the company calls the Colossal Woolly Mouse. The lab mice, which have been modified to have shaggy fur and golden coats, are a demonstration of the kind of gene edits that the company hopes to perform on a much larger scale, modifying Asian elephants to more closely resemble their woolly mammoth ancestors.
The genomes of the Colossal mice were edited at multiple points to change their fur so it was longer, frizzier, and more golden than that of normal lab mice. Some of the mice also had edits to a gene involved in the metabolism of fatty