Genetic engineering company Colossal Biosciences said Tuesday that it will try to resurrect the extinct dodo bird, and it’s received $150 million in new funding to support its “de-extinction” activities.
The dodo was already part of Colossal’s plans by September 2022, but now the company has announced it with all the pomp, circumstance, and seed funding that suggests it will actually go after that goal. The $150 million, the company’s second round of funding, was led by several venture capital firms, including United States Innovative Technology Fund and In-Q-Tel, a VC firm funded by the CIA that first put money into the company in September.
Adding the dodo to its official docket brings Colossal’s total de-extinction targets to three: the woolly mammoth (the company’s first target species, announced in September 2021), and the thylacine, a.k.a. the Tasmanian tiger, the largest carnivorous marsupial.
Colossal’s stated goal is not to simply bring these creatures back for vibes; its contention is that reintroducing the species to their respective habitats would help restore a certain amount of normalcy to those environments.
Mammoths died out about 4,000 years ago on Wrangel Island, off the northeastern coast of Russia. The dodo, a species of flightless bird native to the island of Mauritius, was gone by 1681. The last known thylacine died at a zoo in Tasmania in 1936. Scientists have sequenced the genomes of all three species—the mammoth’s in 2015, the dodo’s in 2016, and the thylacine’s in 2018.
The latter species were driven to extinction by humankind; humans hunted the dodo, introduced predators and pests to its environment, and contributed to its habitat loss. Humans may have played a role in mammoth extinction as well, but the dodo and the thylacine are classic examples of our ability to wipe out species at extraordinary speed.
Following European colonization of Tasmania, settlers cast the thylacine as a threat to sheep flocks (though this threat was hugely overblown), and the Tasmanian government eventually put a bounty on the marsupial’s head. Some experts believe the thylacine may have persisted in the wild for several decades after 1936, but the writing was on the wall for the iconic species.
Colossal also said it is creating an Avian Genomics Group, which will oversee the efforts to resurrect the stocky dodo. The blue-gray bird weighed as much as 50 pounds and had a distinctive curved beak. Perhaps due to the lack of natural predators on Mauritius, the dodo evolved to be flightless. Europeans encountered the birds in 1507, and by about 150 years later they were extinct.
If the company’s work pans out—and that’s a big if—proxy species of those extinct animals will be brought to bear. That’s because the genetically engineered animals produced by Colossal would not be a bonafide mammoth, dodo, or thylacine.
In 2016, the International Union for Conservation of Nature’s Species Survival Commission published a report denoting ground rules for creating proxy species. “Proxy is used here to mean a substitute that would represent in some sense (e.g. phenotypically, behaviourally, ecologically) another entity – the extinct form,” the commission stated, adding that “Proxy is preferred to facsimile, which implies creation of an exact copy.”
De-extinction is something of a misnomer, as this process, if successful, will yield science’s best analogue for an extinct creature, not the creature itself as it existed in the past. De-extinction methods generally rely on using a living creature’s genetics in the resurrection process. That means any 21st-century mammoth will have at least some modern elephant DNA imbued in it, and any nascent thylacine would be produced from the genome and egg of a related species.
Colossal intends to produce its proxy mammoth from an artificial womb, according to National Geographic, rather than using an Asian elephant, which is endangered.
What’s more, behavioral traits of an animal are impossible to extrapolate from a genome alone. How will we know if the mammoth we produce actually acts the way the originals did? Thankfully, there’s some video of thylacines, but other details of the animal—such as the circumstances that may have elicited one of its trademark double-yip vocalizations, of which there are no recordings—are lost to time.
A good reference for the Colossal work is a paper published last year in Current Biology, in which a team of geneticists developed a proof-of-principle model for resurrecting the Christmas Island rat, a species closely related to the extant Norway brown rat.
The team was confident they could reproduce aspects of the extinct rat where areas of the two animals’ genomes largely overlapped; namely genes involving keratin and details like fur color and the shape of its ears. But genes related to the extinct rat’s olfaction (its sense of smell) and its immune responses had little corollary in the genome of the living Norwegian rat. So if the team wanted to bring the rat back in some form, it would need a spoofed immune response and olfactory system.
Similarly, it will be difficult to know whether a proxy thylacine, dodo, or mammoth is behaving as a bonafide version of the animal may have behaved. Lots of animal behavior is taught from parents, but a resurrected mammoth would be alone in the world.
The current plan for the thylacine is to plant the nucleus from a “Thylacine-like cell” into the egg of a genetically engineered Dasyurid egg. Dasyurids are a group of marsupials that includes quolls which the Colossal team deemed the best fit for a thylacine redux. The host Dasyurid’s genome would be engineered to make it more “Thylacine-like,” per Colossal’s website.
Whether or not proxy species are actually produced by startups like Colossal, genetics research done in the name of creating them could help us better understand the relationships between species and how to protect living creatures from threats like disease.
Better understanding species—extinct and extant—on a genetic level is a good thing. How that technology is used, and by whom, is an issue that needs to be handled carefully.