'We didn't know they were going to be this cute'

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https://www.livescience.com/animals/land-mammals/colossal-creates-woolly-mouse-in-new-step-towards-mammoth-de-extinction?utm_medium=referral&utm_source=pushly&utm_campaign=All%20Push%20Subscribers

'We didn't know they were going to be this cute': Scientists unveil genetically engineered 'woolly mice'

3rd March, 2025

Scientists with the company Colossal have created genetically engineered "woolly mice" with thick, golden-brown hair and fat deposits similar to those of cold-adapted woolly mammoths.

Scientists have created genetically engineered "woolly mice" with fur similar to the thick hair that kept woolly mammoths warm during the last ice age.

The biotechnology company Colossal Biosciences unveiled images and footage of the woolly mice on Tuesday (March 4). The adorable rodents mark a milestone in Colossal's project to bring back woolly mammoths by 2028, the company said in a statement shared with Live Science.

"We actually just started this work in mice in September [2024]," Ben Lamm, Colossal's co-founder and CEO, told Live Science.

"We didn't know they were going to be this cute"

Colossal scientists plan to eventually "resurrect" woolly mammoths (Mammuthus primigenius) by first editing cells from the mammoths' closest living relatives, Asian elephants (Elephas maximus), to create elephant-mammoth hybrid embryos with shaggy hair and other woolly mammoth traits. But before the researchers can start working with elephants, they must test the relevant gene edits and engineering tools in mice, which are easier to keep and quicker to breed.

"A mouse model is super useful in this case, because unlike elephants [whose gestation lasts about 22 months], mice have a 20-day gestation," Beth Shapiro, an evolutionary biologist and chief science officer at Colossal, told Live Science.

The short gestation period enabled researchers to design, clone and grow the woolly mice in just six months, Lamm and Shapiro said. Colossal scientists described the results in a study that was uploaded to the preprint database BioRxiv March 4. The study has not been peer reviewed.

The Colossal "woolly mouse" has fur similar to the thick hair that kept woolly mammoths warm during the last ice age. (Image credit: Colossal):

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From WIRED Magazine:

Genetic Explorers

I live in a big city. This, as all city dwellers must learn, means that I am in the position of occasionally encountering a rodent. The omnipresence of rodentia has not warmed me on them, though I admit that the one time a mouse poked his head out of my stove, I found him to be pretty cute. Just a little guy, even. Mice are supposed to be pests, vermin, and subjects of not-always-humane experimentation. Some people (weird ones, usually) keep them as pets. We rarely celebrate them, but this week a specific gaggle of mice had five minutes of fame for being super cute and super fluffy. Colossal Biosciences bred a woolly mouse to have mammoth-like characteristics as part of the company’s woolly mammoth de-extinction efforts. “They are significantly cuter than we anticipated,” the lab said.

The casual gene selection Colossal conducted to create these adorable floofs is built on more than 100 years of research and selective breeding. As Gary Wolf wrote in 2010, in a February feature entitled “How the Inbred Lab Mouse Helps Reprogram the Human Genome,” the mighty lab mouse is the result of generations of scientists working to create the ultimate experimentation subject. “The new mouse is a model in a different way,” says Wolf. “Not a tiny stand-in for a human but a kind of exemplar. We are using it to explore the limits of biological systems, sending it into a future where flesh is blended with code.” Now, researchers can order up any type of mouse that suits their endeavors: fat, thin, blind, deaf, epileptic, predisposed to breast cancer, predisposed to dementia. Woolly.

Wolf’s writing is incisive and at times beautiful. A story about mice evolves into one reflecting on the immeasurable ways that genes express themselves in human existence. It turns out that these half-ounce critters, with their teeny legs and itty-bitty beating hearts, are vital to how we understand ourselves and even more essential to building a better future. I rarely think about these genetic explorers, as Wolf dubbed them, when news breaks of a new treatment, though they are undoubtedly behind it.

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Behold the lab mouse, one of the most important—and flawed—subjects in the history of science.Photograph: Giles Revell:

Video of the mice:

[Chip (OP)]

https://www.wired.com/2010/02/ff-lab-mouse/?utm_source=nl&utm_brand=wired&utm_mailing=WIR_Classics_030725&utm_campaign=aud-dev&utm_medium=email&utm_content=WIR_Classics_030725&bxid=67883001cdeb6340250c3d97&cndid=85787720&hasha=c9edd795ab58c731e64cc2832451a46d&hashc=1e7f7a9239bb44f191dc979b8fe5e634e587dfe020b84a653d2040468a8b342b&esrc=&utm_term=WIR_Classics

How the Inbred Lab Mouse Helps Reprogram the Human Genome

Feb 22, 2010

A simple inbred rodent became one of the most important—and flawed—subjects in the history of science. Next up for the lab mouse: helping to reprogram the human genome.

Take the link to listen to the audio.