Colossal Biosciences Creates "Woolly Mice" with Mammoth Genes

Colossal Biosciences, a US-based biotechnology company, has engineered "woolly mice" by modifying seven genes in mouse embryos. The mice exhibit traits similar to those of woolly mammoths, including long, thick, wavy, and golden fur. This was achieved by identifying genetic variants where mammoths differed from Asian elephants, their closest living relatives, and then finding corresponding variants in lab mice. The scientists edited genes such as FGF5, which regulates hair growth, and MC1R, which influences coat color. Beth Shapiro, chief science officer at Colossal Biosciences, stated that the scientists compared "mammoth genomes" to identify differences from elephants, focusing on genes linked to "coat waviness, hair length." They then sought "mouse versions of those same genes" with variants leading to a "woolly coat." While Colossal Biosciences views this as a milestone, some scientists remain skeptical. Stephan Riesenberg, a genome engineer at the Max Planck Institute for Evolutionary Anthropology, commented, "It's just a mouse that has some special genes." Robin Lovell-Badge of The Francis Crick Institute noted the absence of data addressing cold tolerance in the modified mice.