Colossal Biosciences, founded in 2021 by entrepreneur Ben Lamm and Harvard geneticist George Church, has announced plans to de-extinct and tame the dodo bird, a flightless bird that became a symbol of extinction after it was wiped out by human activity on its home island of Mauritius.

Colossal is already working to breed the woolly mammoth and thylacine (also known as the Tasmanian tiger) and return them to the wild, writes Vice. In this process, the company hopes to introduce new technologies that will find application, in particular, in environmental biology and human health care.

The company turned to Beth Shapiro, an evolutionary biologist at the University of Santa Cruz, with a request to support the project. The team plans to return a “proxy” version of this unique bird — that is, a species with edited DNA rather than an exact clone — to its original habitat in Mauritius.

“I’ve always been fascinated by the dodo,” said Shapiro, who led a team that for the first time fully sequenced the dodo genome. “It’s the poster child, in a sad way, for how human habitat alteration can drive species to extinction.”

The flightless bird was so unique that its closest living relative is the Nicobar pigeon, a colorful flying bird that looks quite different from its famous extinct relative. Its whimsical look has made the dodo a cultural wonder almost from the moment European explorers came across it in the 17th century.

But some of the same characteristics that distinguish birds from the rest of the animal world have made them particularly vulnerable to extinction. Before Europeans introduced invasive animals to Mauritius, there were no mammals that preyed on birds. With no real experience of fighting predators, dodos were docile and easily destroyed. Such predation, as well as the rapid destruction of forest biotopes by man, led to the extinction of the dodo by the beginning of the 18th century.

Shapiro and colleagues are now piecing together a dodo-like animal using genomes sequenced from real specimens of the dodo, as well as those of its close relatives, such as the Nicobar pigeon and the Rodriguez solitaire, another extinct flightless bird that lived on the nearly the Island of Rodriguez.

The return of the dodo will have to begin with its reengineering.

“Once a species is extinct, it’s really not possible to bring back an identical copy,” Shapiro said. “The hope is that we can use, first, comparative genomics so we can get at least one, and hopefully more, dodo genomes that we can use to look and see how dodos are similar to each other, and different from things like the solitaire.”

The team will then compare them to the genomes of the Nicobar pigeon and other pigeons and identify mutations in that genome that may have some phenotypic effect that makes the dodo look like a dodo rather than a Nicobar pigeon.

Getting the right genetic ingredients for a dodo proxy is just the first hurdle in a long scientific quest. Researchers will also have to figure out how to place the dodo embryo in the egg so that a new generation of birds can successfully hatch.

As with many new fields, extinction science has many ethical nuances in addition to technical challenges.

“The question really is, how close will the proxy be to the extinct form?” says Tom Gilbert, director of the Center for Evolutionary Hologenomics at the University of Copenhagen, who recently joined Colossal’s advisory board.”What are you measuring? Genomic similarity? Physical similarity? Similarity in the niche it fills/what it does, even if it doesn’t look the same (e.g. if you can make an elephant able to live in the cold where it acts like a mammoth…is that enough?”

At the same time, Gilbert assured that he will definitely go to see the recreated mammoth, and noted that these charismatic proxy species can be an effective way to raise awareness about the fate of living species that are now under threat of extinction. Lamm and Shapiro also spoke about the potential of proxies to boost conservation and restoration efforts in endangered ecosystems.