When I think about woolly mammoths, Manny from the Ice Age movies is the first thing that comes to mind. I would never think of any modern animals, especially something as small as a mouse. But, in early March, the company Colossal Biosciences showcased its woolly mice to the world!
Woolly mammoths were large elephant-like animals that roamed Europe, Asia, and North America until they went extinct four thousand years ago. For years, scientists believed that extinction was eternal and that there was no way to bring woolly mammoths back to life. Colossal Biosciences is trying to challenge this narrative.
Colossal believes the best approach is to genetically engineer living animals to resemble extinct species. Despite anxieties about potential Jurassic-Park-esque repercussions, Colossal claims that this can only benefit ecosystems. Bringing back mammoths in particular could help slow the melting of ice caps, as the animals provide a layer of insulation which would aid in lowering the ground temperature. This research is currently being done by studying the DNA of extinct animals and identifying the molecular determinants of their key traits. By doing so, Colossal can work on introducing gene variants responsible for an extinct animal’s key traits into living animals via genetic engineering.
Colossal started their work with mice first. Through comparative genomics (i.e. comparing the mouse genome and genes from mammoths), they identified and selected genetic variations associated with long woolly hair and fat storage. These are traits that are likely related to cold tolerance, which was a crucial quality for a mammoth’s survival on the Arctic steppe. They further found that some of the genetic variations were “present already in some living mice,” and decided to combine these variations in a single mouse. Colossal’s scientists then used CRISPR technology and simultaneously edited seven genes in mouse embryos to create mice with long woolly hair and different fat storage, all without any unwanted effects. The results were adorable fluffy mice, like those shown in the photo to the left. This breakthrough has tremendous implications because, as Colossal Chief Scientist Beth Shapiro says, “It confirms that the genes and gene families that we identified using our comparative genomics approach [do create the woolly mammoth traits], and this is the way that we’re going to create mammoths for the future.”
With the confirmation of Colossal’s genetic engineering approach by the creation of woolly mice, scientists now plan to edit the embryos of Asian elephants, the closest living relatives of woolly mammoths. However, this raises a host of ethical issues, as Asian elephants are an endangered species. Many scientists have also spoken out about the possible consequences that Colossal’s genetic engineering could cause. Professor of Biology at the University of Buffalo Vincent Lynch cautions that the vast differences between a mouse and an elephant could lead to unexpected outcomes when Colossal transitions to the elephant genome. Lynch and other scientists argue that the better solution to reducing extinction is to fund work saving the species that are currently on the brink of dying out.
Beyond the impact on the Asian elephants themselves, introducing mammoth-like elephants into the Arctic could bring unintended consequences. As professor of geosciences at the University of Arizona, Karl Flessa, said, “I don’t know what the downside of having a bunch of hairy Asian elephants stomping around in the tundra might be. I don’t know what would happen. [Colossal doesn’t] know what would happen. They can’t really assure me that, ‘Oh, everything will be just fine. Everything will be just like it was back in the Pleistocene.’ I’m not ready to play God like that.”
Colossal has responded to criticism saying that current conservation models don’t work at the speed needed, and thus new tools and technologies need to be utilized to “engineer life in a better way that’s more adaptable to be co-existent with humans.” Colossal will continue working on their plan to reintroduce mammoths back into the Arctic. Their current plan is to create mammoth-like Asian elephant embryos by next year and calves by 2028. Additionally, Colossal wants to try and de-extinct other animals such as the dodo bird and Tasmanian tiger. We just need to wait and see what Colossal will surprise us with next.
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