After an intense study of the mammoth's genetic code, scientists have engineered 'woolly' mice with altered fur thickness, color, and texture to recreate the extinct elephant's adaptations to the cold.
According to researchers at the US biotechnology and genetic engineering company Colossal Biosciences, the mouse's creation is a key step towards the de-extinction of the woolly mammoth – not a revival of an extinct species, but the engineering of a woolly elephant that could thrive on the world's tundras.
The controversial work has been described in a preprint article that awaits peer review. But the floof somewhat speaks for itself.
"The Colossal Woolly Mouse marks a watershed moment in our de-extinction mission," says Ben Lamm, co-founder and CEO of Colossal Biosciences.
"By engineering multiple cold-tolerant traits from mammoth evolutionary pathways into a living model species, we've proven our ability to recreate complex genetic combinations that took nature millions of years to create. This success brings us a step closer to our goal of bringing back the woolly mammoth."
An extinct species is a bit like Humpty Dumpty. There are a lot – a hell of a lot – of very small pieces, and working out where they go and what they do is no small task. But you can start small; like, mouse small.
Led by geneticist Rui Chen of Colossal Biosciences, an international team of scientists made a painstaking study of several species of extinct mammoths and modern-day elephants.
They analyzed 59 genomes from mammoths that lived anywhere between 3,500 and over 1,200,000 years ago, including woolly mammoths (Mammuthus primigenius), steppe mammoths (Mammuthus trogontherii) and Columbian mammoths (Mammuthus columbi).
They also studied the genome of Asian elephants (Elephas maximus), for a total of 121 genomes.
These analyses allowed the researchers to identify mammoth genes that were distinctly different from those of the Asian elephant. From there, they were able to home in on seven genes associated with the luxurious hair of the woolly mammoth, as well as other adaptations suited for colder environments such as fat retention and distribution for warmth.
The team used three different gene editing techniques – RNP-mediated knockout, multiplex precision genome editing, and precision homology directed repair – to make eight simultaneous edits to these seven genes in mouse embryos, resulting in several marked changes from the parent mice.
The engineered mice had hair that is up to three times longer than that of wild mice, in addition to being woollier and wavier, with a curl to their whiskers. Those coats are also lighter, like the coats of mammoths, appearing more golden in color, compared to the darker hued fur of wild mice.
The hope, one day, is that similar genetic modification of Asian elephants – closely related to extinct mammoths – will restore mammoths to the world. That may in the end prove unattainable, but some argue the work is still worth doing. The lessons learnt along the way could be a powerful tool for saving other species that are facing extinction today.
"In addition to the immense scientific challenge that still lies ahead for the Colossal team, the threats that caused the demise of the woolly mammoth have only worsened in recent years. Therefore, it is somewhat fanciful to believe that one day we will again have self-sustaining populations of mammoths roaming Siberia," says conservation biologist Damien Fordham of the University of Adelaide in Australia, who was not involved in the research.
"Nevertheless, the technology could potentially rescue living species from extinction through engineering of their phenotypes. For example, it could be used to reestablish warm tolerant traits lost in dwindling populations of species who are at risk of extinction from human-driven climate change."
Colossal has been working on a way to restore mammoths to Earth for some years in what they claim to be a bid to save our planet from the ongoing deleterious effects of human activity.
"Never before has humanity been able to harness the power of this technology to rebuild ecosystems, heal our Earth, and preserve its future through the repopulation of extinct animals," Lamm explained in 2021.
"In addition to bringing back ancient extinct species like the woolly mammoth, we will be able to leverage our technologies to help preserve critically endangered species that are on the verge of extinction and restore animals where humankind had a hand in their demise."
So let's sit back, and appreciate the glorious floof and the hope it represents.