Colossal Biosciences, the headline-grabbing, venture capital-funded juggernaut of endangered species science, announced plans to revive the dodo on January 31st. It is debatable whether it is feasible to “resurrect” the appearance of extinct flightless birds.
The company, founded in 2021 by tech entrepreneur Ben Lam and Harvard University geneticist George Church, first said it would recreate a mammoth. announced the initiative. His $150 million follow-on investment, now reported as the launch of the new Avian Genomics Group, adds the long-disappeared dodo to the lineup.
In the world of extinct animals, the dodo carries heavy symbolic weight. Native to Mauritius in the Indian Ocean, it became extinct in the mid to late 17th century after humans arrived on the island. Standing about one meter tall and weighing between 15 and 20 kilograms, this ungainly bird symbolizes a kind of evolutionary misfortune. It was supposed to be afraid of humans, but it wasn’t. The birds walked lightly on the sailors, so that the history they received continued, and they did not flinch when their comrades were killed around them. The dodo, which reproduces by laying a single egg on the ground, was also preyed upon by other species such as monkeys and rats brought in by humans. No one dies better than the dodo.
Beth Shapiro, Chief Paleogeneticist and Scientific Advisory Board member at Colossal Biosciences, said: Shapiro, who is also a professor of ecology and evolutionary biology at the University of California, Santa Cruz, has studied the dodo since the science of paleogenetics was in its infancy. In 2002 she published her research. chemistry Describes how her team extracted a small piece of bird mitochondrial DNA (mtDNA). DNA in small organelles called mitochondria that is passed from mother to child. A fragment of its mtDNA indicated that the dodo’s closest living relative was the Nicobar pigeon. Then, in 2022, Shapiro announced that her team at the University of California, Santa Cruz had reconstructed the entire dodo genome.
The journey from mtDNA to genomes has taken decades, but the journey from genomes to living, breathing animals is even more daunting, involving a vast and highly complex set of interacting problems. increase. Technically, the species can be revived by cloning DNA from remnant cells. In practice, this has been impossible to achieve, mainly due to the lack of viable DNA. Most de-extinction programs aim to recreate proxies of extinct animals through genetic engineering, editing the genomes of closely related species to replicate the genomes of the target species. The edited genome is implanted into the egg cell of its related species and developed. This process ensures that development proceeds correctly, that animals are born safely, that they are cared for by suitable surrogate parents, that they are fed a nutritious diet, and that they are housed in an appropriate environment. need to do it.
Colossal Biosciences is trying to solve all these problems at once. “We are not yet ready to start transferring embryos to surrogate mothers,” says Lam, although the company now has a team working on the cloning methodology needed for that process. We also have multiple teams working in parallel on issues such as computational biology, cell engineering, stem cell reprogramming, embryology, protein engineering, and animal husbandry.
One of the biggest challenges in reconstructing the dodo is the issue of genomics for all birds. For mammals, the process is similar to that used to create Dolly the sheep. This process is the first animal in the world to be successfully cloned from the adult cells of an adult mammal. But Shapiro says, “You can’t clone a bird.” Cloning requires access to an egg cell that is ready for fertilization but not yet fertilized. “We don’t have access to bird egg cells at the same developmental stage as mammals,” he explains. Colossal Biosciences is investigating the process of extracting avian primordial germ cells (PGCs) from avian eggs. If this process goes well, the pigeon PGC can be manipulated to eventually grow into a dodo-like bird. Ultimately, Shapiro said: So the egg size will be constant. “
The first steps of genome editing are difficult in birds, but the next steps should be easier. For mammals, scientists do not yet know how modified embryos of extinct species interact with the host species’ intrauterine environment. That step will be simpler in birds, Shapiro explains.
More questions arise when the recreated animals are born. Most animals are a mixture of instinctive behaviors that arise from genetic programming and social behaviors learned from parents and, in the case of social animals, from herds or groups. But there is no way to reconstruct the unique natural history that shaped the social behavior of the dodo and other extinct animals, and often no way to even know what it was. “No one can tell a dodo how to become a dodo,” says Mikkel Sinding, a postdoctoral researcher in paleogenomics at the University of Copenhagen. In this sense, the term de-extinction is a misnomer.impossible to bring back of Even if it were possible to create a bird with the dodo genome.
Beyond action, Dodo Proxies must survive in a world vastly different from the one over 300 years ago when the Dodo went extinct. However, little is known about how the dodo functioned in the ecosystem. Birds lived only in the forests of Mauritius. They did not have large predators. They are slow breeders, laying one egg per year. And, from accounts of ancient sailors, it is believed there were once thousands.
“The goal here is to create animals that can become physically and psychologically well in the environment they live in,” says Shapiro. “Reviving a functional equivalent of the dodo requires finding, identifying, or creating habitats in which the dodo can survive.” Shapiro points to environmental restoration in Mauritius and the surrounding islands. doing. Work focused on restoring the dodo’s habitat could have ramifications for other endemic plants and animals, and even the reintroduced birds could directly contribute to the restoration of their own ecosystems. A giant tortoise, introduced to replace an extinct species on an island near Mauritius, is helping to revive native ebony trees by eating the fruit and scattering the seeds across the landscape.
Having extracted ancient DNA from Pleistocene wolves, woolly rhinos and aurochs, Sinding was surprised and excited to hear that Colossal Biosciences was planning to recreate the dodo. He believes the company is likely to have a faster success with birds than with mammoths or thylacines. However, he adds that this depends on your definition of success. “You can say that you’ve edited the genome of something and remade the species,” says Sinding. “But is it really a seed?”
“The dodo is a good choice because fetal development occurs in a short period of time in the egg rather than in the surrogate mother, unlike mammoths, which elephants must gestate for nearly two years,” says Sinding. “It’s a little easier to work with a chick than a chick.” Should the money be used to protect it,” he adds.
Tom Gilbert, Director of the Danish National Research Foundation Center for Evolutionary Horogenomics, recently joined the Scientific Advisory Board of Colossal Biosciences. In 2022, before joining the board, Gilbert told Technology Networks that he loves the “ideas and technology behind the rewilding of extinct species.” But he wondered about the impact of human morality on species choice. Has the pathogen been eradicated? “
Extinction of the dodo “doesn’t solve the extinction crisis,” says Shapiro. “Extinction is forever.” But in pursuing the question of dodo de-extinction, Colossal Biosciences is also developing essential tools for bird genomics, she explains. This includes tools to save the genes of currently endangered species. For example, editing genetic diversity to restore populations of endangered birds. As such, the 21st-century dodo has the potential to help save all bird species.
The dodo is just one of many lost birds. According to his 2022 report for BirdLife International, 161 bird species have been classified as extinct since 1500. But Colossal Biosciences is using this organism’s importance to urge scientists and the general public to tackle all the problems of extinction. “We could have picked a lot of birds,” Shapiro said, raising his right arm to reveal a dodo tattoo. “I happen to love dodos.”
