How Colossal Biosciences Is Pioneering De-Extinction Technology
The biotech firm's breakthroughs in genomic reconstruction could revolutionize conservation efforts.
1Dire wolf resurrection milestone
Colossal Biosciences successfully birthed three dire wolf pups in 2025 through surrogate dogs, marking a breakthrough in de-extinction technology. The pups - Romulus, Remus, and Khaleesi - exhibit key ancient traits including massive size (reaching 120lbs in their first year) and distinctive white fur coats. These results were achieved through 20 precise CRISPR edits to modern gray wolf DNA, with 15 edits specifically targeting recovered dire wolf genetic markers. The project required painstaking recovery of ancient DNA from 13,000-86,000 year old fossils found in Ohio and Idaho.
2Strategic trait selection
The team prioritized visible phenotypic changes for immediate validation, selecting white fur as their primary marker. Evolutionary biologist Beth Shapiro explained this allowed for instant visual confirmation of successful gene editing. Other traits like increased size and musculature were chosen for their evolutionary significance but require longer observation periods. The team avoided certain ancient genes associated with Waardenburg syndrome risks in humans, instead opting for safer modern gray wolf genetic variants that produced similar phenotypes without health complications.
3Red wolf conservation application
Colossal redirected resources from the dire wolf project to clone four red wolves, a species with only 16 remaining in the wild. Partnering with the Gulf Coast Canine Project, they accessed 'ghost' DNA from historic red wolf populations that had interbred with coyotes. This approach addresses the critical genetic bottleneck facing captive breeding programs that currently rely on just 14 individuals. The technology could inject much-needed diversity into the red wolf gene pool, potentially saving the species from extinction.
4Thylacine restoration potential
Chief Biology Officer Andrew Pask highlights the thylacine (Tasmanian tiger) project as having significant ecological implications. As a cornerstone species whose extinction caused trophic downgrading in Tasmania, its restoration could rebalance local ecosystems. The genetic tools developed could then be applied to other endangered Australian marsupials. Australia currently suffers the world's highest mammal extinction rate, making this technology particularly valuable for conservation efforts in the region.
5Iterative genome assembly
Colossal developed a novel 'iterative assembly' technique to reconstruct the fragmented dire wolf genome from ancient fossils. This method alternates between jackal and wolf genome scaffolds, gradually creating a hybrid reference genome. For their 13,000-year-old tooth specimen, they achieved 3.4x depth of coverage; for the 58,000-86,000 year old skull, 12.8x coverage. This approach has since been adopted by other ancient DNA research labs and applied to specimens dating back millions of years.
6Beyond de-extinction
While marketed as de-extinction, Colossal's work has broader scientific implications. Their genomic techniques enhance paleontologists' ability to study prehistoric creatures and ecosystems. The company has expanded into avian cloning technology and partnered with the U.S. Fish and Wildlife Service on the BioVault project to sequence over 2,300 endangered species. They're also collaborating with IUCN to modernize conservation efforts, demonstrating applications far beyond resurrecting charismatic megafauna.
Original article: Gizmodo — How Colossal Biosciences Is Pioneering De-Extinction Technology