A version of the dodo bird (Raphus cucullatus) could make a return someday soon. Colossal Biosciences announced this week several milestones in its quest to bring the extinct species back to life.<\/p>\n
On Wednesday, the Dallas-based company reported that its researchers at the Avian Genetics Group have successfully grown pigeon primordial germ cells (PGCs) in the lab, a scientific first. They also bred gene-edited chickens intended to serve as potential surrogates for the dodo and other extinct birds. Those accomplishments are crucial to the company\u2019s plans to functionally restore the dodo to the land of the living.<\/p>\n
\u201cColossal\u2019s breakthrough in culturing pigeon PGCs solves a fundamental roadblock that has stymied bird genetic engineering for decades,\u201d Colossal CEO and co-founder Ben Lamm told Gizmodo.<\/p>\n
How to bring back an extinct bird <\/p>\n
Colossal bills itself as a functional \u201cde-extinction\u201d company. Its stated goal isn\u2019t to perfectly replicate the genome of an extinct animal; rather, it\u2019s to resurrect \u201cthe key traits and ecological functions of extinct species\u201d using the smallest amount of precise genetic edits possible, Lamm said.<\/p>\n
Earlier this April, Colossal reported<\/a> its first success: the breeding of three wolves modified to share some of the genetic makeup of the dire wolf (Aenocyon dirus), an extinct, larger relative of the gray wolf that died out nearly 10,000 years ago.<\/p>\n The company also has pledged to bring back and re-wild the woolly mammoth, the Tasmanian tiger, and the dodo bird. That said, resurrecting an extinct bird is an entirely different challenge compared to bringing back mammals like wolves.<\/p>\n \u201cUnlike mammals that can be cloned, birds require a completely different approach. You have to edit their \u2018germ cells\u2019 (which become sperm and eggs) and then breed those edited cells into the next generation,\u201d he explained.<\/p>\n Scientists have previously learned how to edit the germ cells of chickens and geese, but Colossal\u2019s scientists are the first to have successfully tweaked the germ cells of pigeons, the broad group of birds that the dodo belongs to\u2014no easy feat. The researchers tested 300 combinations of growth factors, small molecules, and other ingredients before finding the optimal formula for growing the edited PGCs.<\/p>\n The company has also bred chickens without their own germ cells, allowing scientists to insert edited PGCs in their place. Ideally, this means that when these chickens reproduce, they\u2019ll actually lay eggs containing pigeon genetics, not chicken.<\/p>\n Lastly, its scientists have fully sequenced the genomes of the dodo\u2019s closest relatives, the extinct Rodrigues solitaire (considered the dodo\u2019s sister species) and the still-living Nicobar pigeon, the latter of which will serve as the base template for the team\u2019s dodo revival project. This information will enable Colossal scientists to plot the genetic edits needed to make a Nicobar pigeon into a dodo-like bird.<\/p>\n \u201cThese advances create a clear pathway: edit Nicobar pigeon germ cells with dodo traits, inject them into surrogate chickens, breed the results, and eventually produce birds with dodo characteristics,\u201d Lamm said.<\/p>\n The argument over de-extinction <\/p>\n While many scientists have praised Colossal for its genetic innovations\u2014like creating its version of a dire wolf\u2014others have criticized the company for labeling its projects as \u201cde-extinction.\u201d<\/p>\n Wolves, dodos, and other animals contain troves of genetic information, and critics have argued that the relatively few edits Colossal is performing in their specimens simply don\u2019t come close to bridging the gaps between an extinct species and its closest living relatives.<\/p>\n \u201cWe\u2019re focused on results, not labels. Whether critics want to call our animals \u2018de-extinct dodos\u2019 or \u2018dodo-functional birds\u2019 doesn\u2019t change their conservation value.\u201d <\/p>\n Colossal stands by its approach, however. It notes that some conservation organizations have advocated<\/a> for creating \u201cproxy\u201d versions of extinct species as a way to restore biological diversity in an area\u2014a goal the company feels is aligned with its mission. Lamm also argues that since each genetic edit carries some risk, keeping them to a minimum also helps ensure the safety and health of their animals.<\/p>\n \u201cWe\u2019re focused on results, not labels. Whether critics want to call our animals \u2018de-extinct dodos\u2019 or \u2018dodo-functional birds\u2019 doesn\u2019t change their conservation value,\u201d he said. \u201cWhat matters is whether they can restore lost ecological functions, enhance ecosystem resilience, and help address the biodiversity crisis all while inspiring the next generation.\u201d<\/p>\n