Scientists plot the resurrection of a bird that's been extinct since the 17th century

ByKatie Hunt, CNN
Thursday, February 2, 2023
Scientists recreating extinct Dodo bird
Scientists plot the resurrection of a bird that's been extinct since the 17th century

No other animal is as inexorably linked with extinction as the dodo, an odd-looking flightless bird that lived on the island of Mauritius in the Indian Ocean until the late 17th century.

The arrival of sailors brought with them invasive species like rats and practices like hunting. They doomed the dodo, which showed no fear of humans, to extinction in the space of just a few decades.

Now, a team of scientists wants to bring back the dodo in a bold initiative that will incorporate advances in ancient DNA sequencing, gene editing technology and synthetic biology. They hope the project will open up new techniques for bird conservation, CNN reported.

"We're clearly in the middle of an extinction crisis. And it's our responsibility to bring stories and to bring excitement to people in way that motivates them to think about the extinction crisis that's going on right now," said Beth Shapiro, a professor of ecology and evolutionary biology at the University of California, Santa Cruz.

Shapiro is the lead paleogeneticist at Colossal Biosciences, a biotechnology and genetic engineering start-up founded by tech entrepreneur Ben Lamm and Harvard Medical School geneticist George Church, which is working on equally ambitious projects to bring back the woolly mammoth and the thylacine, or Tasmanian tiger.

Shapiro said that she had already completed a key first step in the project - fully sequencing the dodo's genome from ancient DNA - based on genetic material extracted from dodo remains in Denmark.

The next step was to compare the genetic information with the dodo's closest bird relatives in the pigeon family - the living Nicobar pigeon, and the extinct Rodrigues solitaire, a giant flightless pigeon that once lived on an island close to Mauritius. It's a process which would allow them to narrow down which mutations in the genome "make a dodo a dodo," Shapiro said.

Challenges to resurrecting the dodo

However, the subsequent work that's needed to resurrect the animal - programming cells from a living relative of the dodo with the lost bird's DNA - will be significantly more challenging. Shapiro said she hopes to adapt an existing technique used involving primordial germ cells, the embryonic precursors of sperm and eggs, that has already been used to create a chicken fathered by a duck.

The approach involves removing primordial gems cells from an egg, cultivating them in the lab and editing the cells with the desired genetic traits before injecting them back to an egg at the same developmental stage, she explained.

Even if the team is successful in this high-stakes endeavor, they won't be making a carbon copy of the dodo that lived four centuries ago, but an altered, hybrid form.

However, Shapiro said that perfecting these synthetic biology tools will have wider implications for bird conservation. The techniques could allow scientists to move specific genetic traits between bird species to help protect them as habitats shrink and the climate warms.

"This technology, which works in chickens.... it would be amazing to get this to work in lots of different birds across the bird tree of life because that will be hugely impactful for avian conservation," Shapiro said.

"If we find that there's something that provides immunity against a disease that's hurting a population, and you know what the genetic changes underlying that immunity or that ability to fight off that disease is - maybe we can use these tools to transfer that even between closely related species," she added.

Mike McGrew, a senior lecturer and personal chair in avian reproductive technologies at the Roslin Institute at the University of Edinburgh, described the project as a "moon launch for synthetic biology." His work involves turning commercial egg-laying hens into surrogates for rare chicken breeds revived from frozen primordial germ cells.

"The idea is you have to now be able to do this with pigeon species. And that's the big, hard part jumping from chicken species, which many labs in the world do, to other bird species," said McGrew, who is not directly involved in the dodo project but is part of Colossal's scientific advisory board.

"I've been trying for about 10 years to culture germ cells from other bird species. It's hard," he said.

Investment in de-extinction

Whether or not Colossal and its team of scientists are ultimately successful in their quest to bring back the dodo and other extinct creatures, de-extinction projects, and the technological breakthroughs they may generate, have investors excited. Colossal also announced Tuesday that it has raised an additional $150 million, bringing the total amount of funding raised since the company launched in 2021 to $225 million.

Critics, however, say the vast sums involved could be better put to use protecting the 400 or so bird species, and many other animals and plants, that are listed as endangered.

"There's so many things that desperately need our help. And money. Why would you even bother trying to save something long gone, when there's so many things that are desperate right now?" said Julian Hume, an avian paleontologist at London's Natural History Museum, who studies the dodo.

Dodo myths

Hume said there's very little known about the dodo and lots of myths surround the creature. Even the origin of its name is a mystery, though he thinks it stems from the sound of the call the bird was said to have made - a low-pitched pigeon-like coo.

Millions of years ago, the dodo's ancestors lived in Southeast Asia, and when sea levels were low, it island-hopped its way to Mauritius, where it became isolated without predators once sea levels rose.

"Flight is very (energetically) expensive. Why bother maintaining it if you don't need it? All the fruit and food is on the ground, and when you've become flightless, you can become big. That's what the dodo did, it just got bigger and bigger and bigger," Hume said.

According to a digital 3D model of the bird Hume developed based on a skeleton from the Durban Natural Science Museum in South Africa, the dodo once stood around 70 centimeters (2.3 feet) tall and weighed about 15 to 18 kilograms (33 to 39 pounds).

The model revealed the dodo was also likely more agile than the illustrations that depict it as a fat, ungainly bird might suggest.

We have the dodo to thank for introducing the idea of extinction to the world - a sad achievement still felt in the phrase as "dead as a dodo."

Back in the 1600s, before the first dinosaur fossils were widely known, "the concept of extinction didn't exist. Everything was God's creation and they were here forever. The idea that something can be wiped out was just not in anybody's vocabulary," Hume said.

"It was such an extraordinary bird, even at the time of discovery," he added. "They disappeared rapidly. So when people wanted to know more about them, there was none left."

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