The “woolly mouse” Colossal has fur that resembles the thick hair that protected woolly mammoths during the last ice ages. (Photo credit: Colossal)
Researchers have created genetically modified “woolly mice” with fur that resembles the thick hair that kept woolly mammoths warm during the last ice ages.
Biotech company Colossal Biosciences unveiled photos and videos of woolly mice on Tuesday (March 4). The cute rodents represent a major milestone in Colossal's project to bring back woolly mammoths by 2028, the company said in a press release published by Live Science.
“We actually just started this work with mice in September [2024],” Ben Lamm, Colossal’s co-founder and CEO, told Live Science. “We didn’t expect them to be so cute.”
Colossal scientists eventually plan to “resurrect” woolly mammoths (Mammuthus primigenius) by first editing cells from mammoths’ closest living relatives, Asian elephants (Elephas maximus), to create elephant-mammoth hybrid embryos with long hair and other woolly mammoth characteristics. Before the researchers can work with elephants, however, they must test the gene edits and engineering tools in mice, which are easier to maintain and breed.
“The mouse model is very useful in this case because, unlike elephants [whose gestation period is about 22 months], mice have a 20-day pregnancy,” Beth Shapiro, an evolutionary biologist and chief scientific officer at Colossal, told Live Science.
The short gestation period allowed the researchers to engineer, clone, and grow the woolly mice in just six months, Lamm and Shapiro note. The Colossal scientists described their findings in a study that will be uploaded to the preprint database BioRxiv. The study has not yet been peer-reviewed.
Downy rodents
To create the woolly mice, the researchers altered seven genes in the rodents, six of which were linked to fur texture, length, and color. The scientists chose these genes by screening for DNA sequences that control hair growth in mice and that have evolutionary links to sequences that gave woolly mammoths their thick coats.
“We didn’t take mammoth genes and insert them into mice,” Shapiro explained. “We looked for mouse gene variants that we thought would be beneficial to mammoths, and then we created mice that had many of those changes at once.”
Most of the modifications “switched off” genes that are normally active in the mice. For example, the scientists blocked the FGF-5 gene, which regulates hair length, resulting in the mice having hair three times longer than normal lab mice.
Sourse: www.livescience.com
