A Texas-based biotechnology firm, Colossal Biosciences, is making significant progress in its ambitious plan to genetically engineer a version of the dodo, the iconic flightless bird that vanished from existence over 400 years ago. The dodo has become a symbol of extinction, and the company’s recent advancements mark a pivotal moment in what they describe as a groundbreaking endeavor.
Colossal's scientists have successfully cultured specialized cells from the rock dove, commonly known as the pigeon, which is the dodo's closest living relative through a shared family lineage. Although the ultimate goal of creating a living, breathing dodo is still years away, this achievement is deemed a "pivotal step" toward the long-term vision.
“This is the really important step for the dodo project, but also for bird conservation, more broadly,” stated Beth Shapiro, the Chief Science Officer at Colossal. Shapiro emphasized the importance of this milestone, indicating that it will enable the team to advance their work on the dodo project significantly.
The company has generated excitement and some controversy in the scientific community, particularly after announcing the birth of three dire wolf pups in April. By employing ancient DNA, cloning, and gene-editing technologies, Colossal claimed to have resurrected this predator that roamed the Earth 10,000 years ago. This process, referred to as de-extinction, aims to bring back other extinct species, including the woolly mammoth, the thylacine (Tasmanian tiger), and the moa.
On Wednesday, Colossal announced it had raised an additional $120 million, bringing its total funding to $555 million since its inception in September 2021. These funds are crucial for advancing their research in genetic engineering, particularly for species like the dodo, which presents unique challenges due to its reproductive biology.
The methodologies necessary for resurrecting a bird like the dodo differ from those used in mammals. Unlike mammals, birds develop in eggs, making cloning infeasible. “With birds, the slowest part of this process is that we have to make two generations,” Shapiro explained. “We can’t clone the cells, so we have to make moms and dads separately and then breed them in order to get both copies of the gene to be modified.” This complexity makes the dodo project particularly challenging.
Colossal's recent announcement highlighted their breakthrough in culturing a vital type of cell known as a primordial germ cell (PGC). These cells act as precursors to egg and sperm cells and are essential for the company's dodo project. The team focused on the rock pigeon due to its widespread breeding and its distant relation to the dodo.
Previously, scientists managed to culture PGCs from species such as chickens and geese, but those methods had limited success with other bird species. Anna Keyte, Colossal’s avian species director, noted that after testing over 300 different recipes, the team finally discovered a combination that allowed pigeon germ cells to grow for an impressive 60 days.
The next phase involves using the cultured cells to create live rock pigeons birthed by surrogate chickens, which will serve as a proof of concept. Simultaneously, the team is working on culturing PGCs from the Nicobar pigeon, which is more closely related to the dodo. Colossal has established a breeding colony of Nicobar pigeons in Texas and has begun collecting primordial germ cells.
To achieve their ultimate goal, Colossal must edit the Nicobar pigeon’s germ cells with dodo traits using genomic data preserved in museum specimens. These edited PGCs would then be injected into the embryos of genetically modified chickens, which are easier to manage than pigeons and can be sterilized to prevent them from producing their own germ cells.
While Colossal’s advancements in genetic engineering are notable, some critics argue that truly resurrecting an extinct animal is impossible. They contend that any attempt would only result in a genetically modified hybrid species rather than an authentic dodo, potentially diverting attention from the urgent need to protect existing species and ecosystems.
Colossal has clarified that the objective is not to create an identical replica of the extinct species but rather to develop functional copies with key traits. “Dodos belonged to the pigeon and dove family, so the scientists only need to insert dodo-unique genes into the germ cell or edit the pigeon genes to make them dodo-like,” explained Scott MacDougall-Shackleton, cofounder of the Advanced Facility for Avian Research.
The research conducted by Colossal may have broader implications for avian conservation. Cock van Oosterhout, a professor of evolutionary genetics, emphasizes the potential to apply these genetic techniques to help endangered species adapt to changing environments and diseases. “Can we now find the resistant variant, maybe in a historic sample, or in a closely related species that we know is resistant to a particular pathogen?” he posed.
While Colossal's technology offers exciting possibilities, experts caution that it is only a small part of the larger conservation puzzle. “What we need to do as a society is really prevent extinction, prevent habitat loss,” van Oosterhout concluded, highlighting that technology alone cannot solve the biodiversity crisis.
