Could this synthetic egg bring back extinct birds? Researchers urge caution

The de-extinction company Colossal Biosciences says it has developed a key technology for bringing back extinct birds and rescuing endangered ones: an artificial egg.

The device — a 3D-printed lattice shell that protects a transparent silicon membrane — has ‘hatched’ around two dozen chicken and quail. Colossal, based in Dallas, Texas, hopes to use the technology to resurrect the extinct South Island giant moa (Dinornis robustus), a 3-metre-tall New Zealand bird that laid eggs the length of a rugby ball.

Scientists say that the artificial egg — which is detailed in a 19 May press release and accompanying video, but not in a paper or preprint — could represent a genuine advance on work by other researchers. In previous studies, chicks were hatched from artificial eggs made of materials such as plastic films and cups¹. But researchers have many unanswered questions.

“It could be really important, it could be fantabulous,” says Paul Mozdziak, a stem-cell biologist at North Carolina State University in Raleigh. “Without data, it’s really impossible to judge what the true impact is.”

The company has no current plans to describe the artificial egg in a paper, says Colossal’s chief executive, Ben Lamm. The firm hopes to commercialize the technology but will make it available for conservation efforts, he adds.

“There’s an immediate group of people in zoos and conservation breeding facilities that could use this technology,” says Ben Novak, who leads an effort to bring back the passenger pigeon (Ectopistes migratorius) at the non-profit organization Revive & Restore in Sausalito, California.

Scrambled history

Researchers have been working for decades to hatch birds from artificial eggs. The first successful report was in 1998 using quail embryos. Researchers transferred the contents of natural, fertilized eggs into glass vessels after incubating them for two days².

Later efforts introduced transparent plastic cups to track development³, and transferred embryos to artificial eggs immediately after they had been laid^4,5, says Yutaka Tahara, a teacher at Oihama High School in Chiba, Japan, who conducted some of the work.

Tahara, who hatches chicks from artificial eggs with his students, says the main advance of Colossal’s artificial egg seems to be the membrane the company has created, which enables chick development at atmospheric levels of oxygen. The artificial eggs he and others have made, by contrast, require high levels of supplemental oxygen as hatching approaches.

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But this can lead to damage to tissues, DNA and proteins, says Andrew Pask, Colossal’s chief biology officer, “so it does not lead to long-term healthy animals.” The company’s egg has a transparent window on the top, which should allow researchers to track embryo development, including the effects of gene edits aimed at recreating traits such as the beak shape of extinct birds. “They were all things that went into that design to take the artificial egg completely next level,” Pask adds.