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Dead as a dodo? The unsettling bid to bring back extinct species

The writer is a scientific observer.

Portuguese sailors first spotted the creature in Mauritius in the early 16th century and reportedly named it “dudo”, meaning “fool”. The trusting, plump, flightless bird has become a sitting duck for hunters and easy prey for introduced species such as cats and dogs.

The last dodo is believed to have been hunted in the 1660s. Now scientists want to bring it back. Colossal Biosciences, a US genetics startup that describes itself as an “extinction company” and is already targeting the woolly mammoth and the Tasmanian tiger, said Tuesday it will try to revive extinct species through genome editing.

Ben Lamm, co-founder of Colossal with Harvard University genetics professor George Church, said its goal is to reverse human-caused biodiversity loss and is “excited to work to bring new species back to the planet.” The company says its focus is on developing conservation technologies that can be given away for free and public health.

The restored view will not be a facsimile of the original, but rather a double. According to one of the company’s own consultants, it is not currently possible to create a real dodo.

Colossal’s “proxy species” bestiary raises other questions as well. These include the practical problems of bringing altered embryos to term; the ethics of releasing resurrected species into habitats that have since changed; whether the resurrected animals will fulfill the ecological function for which they were created; and whether conservation is better at protecting existing endangered species.

However, investors are piling up. Tuesday’s announcement revealed an oversubscription for a $150 million funding round, bringing the total investment since Colossal’s founding in 2021 to $225 million. Supporters include bitcoin entrepreneurs Cameron and Tyler Winklevoss, as well as Thomas Tull, former CEO of Legendary Entertainment.

The strategy for resurrecting the dodo is to first sequence its genome using bone samples and other fragments, and then edit the genome of a cell of a close relative, the Nicobar pigeon, to resemble that of the dodo. This genetically modified cell will then be used to create an embryo. The resulting chick will be something between a Nicobar pigeon and a dodo.

Nicobar is like a dove; dodo is more like a turkey. Tom Gilbert, professor of paleogenomics at the University of Copenhagen and recently appointed to Colossal’s scientific advisory board, has previously wondered how representative any resurrected species would be. “There is no way to bring back a real dodo, which is defined as being genetically identical to an extinct form,” Gilbert tells me. But despite his concerns about rebirth, he says the doppelgänger can send a powerful message: “If an animal that looks like a dodo stops people from destroying what we have left…. . or stops them from buying illegally traded animals. . . I 100% support this idea.”

Unlike cloning, which requires a cell from a living animal, recreating an extinct species involves collecting genetic keys from ancient DNA fragments and filling in the gaps using the genome of a closely related surviving species. Last year, Gilbert’s team attempted to reconstruct the genome of an extinct Christmas Island rat, using two preserved skin samples and a Norwegian brown rat as a surviving reference species. They mapped 95 percent of the extinct genome, but that wasn’t enough to bring it back: the missing 5 percent covered important survival functions like immunity.

Cloned and hybrid embryos are also associated with high rates of birth defects. The only known attempt to clone a recently extinct animal, the Iberian goat, required 57 embryos, resulting in one calf dying minutes after birth.

Helen Pilcher, whose 2016 book Bring back the king researched extinction science, says that without a strong environmental case for dodo resurgence, she would rather invest resources in, say, the conservation of the last two northern white rhinos.

Professor Beth Shapiro, Colossal’s lead paleogeneticist, acknowledged that the role of dodos in the Mauritius ecosystem is not well understood, but added that the creation of “functionally equivalent” species would advance conservation technologies.

Colossal hopes to debut its replica mammoths in 2028, which lack tusks to scare off poachers. Dodos and Tasmanian tigers may appear earlier.

However, blockbuster science does not make up for low-budget management. Meanwhile, the International Union for Conservation of Nature lists more than 42,000 real species that are now threatened with extinction. It is not too encouraging to think that one day they will return in the form of proxies.

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