I was crouched on the ground 50 feet away from the aurochs.
At least it seemed like one. Eight generations of backbreeding have revived an animal reminiscent of the giant cow that crashed from Earth’s biota in 1627. The pitch-black beast had forward-pointing horns like the long-extinct aurochs. His shoulders and neck were similarly muscular. The bull’s legs were long and athletic. It had a yellow “eel stripe” along its spine, which is a characteristic of aurochs. As I watched him pull weeds from his Dutch fields on a gray March afternoon, I thought about the art on the walls of Chauvet’s cave. If extinction was possible, we were considering it.
But the expert crouching next to me didn’t call it an aurochs. Oscar Campana Cárdenas, director of operations at Dutch nonprofit organization Glazelands Rewilding, called it a “tauros.” In fact, everyone who worked with Cárdenas called it that. This careful labeling of the creature before me seemed strange. The aurochs’ physical resemblance was striking, and the nostalgic yearning was undeniable. But the deliberate choice of words made one thing clear. Glazelands Rewilding does not consider itself to be in the business of eradicating extinction. I believe that extinction will last forever.
“We’re not actually making anything extinct,” says the environmental philosopher. “You’re making something else.”
The genomics revolution has created fascinating new possibility For preservation. A century and a half after Gregor Mendel proposed the mysterious unit of genetics in the pea, scientists now have the tools to manipulate an organism’s genome. Conservation biotechnologists have been experimenting with ways to help endangered species. For example, adding genes to increase genetic diversity. black footed ferret Or DNA could be cloned to make medicines that were once made from blood. horseshoe crab.
While these techniques are promising, the holy grail for some conservation biotechnologists has been bringing extinct animals back from the dead. If we had a complete map of the genome of a lost species, it would theoretically be possible to reconstruct it in the lab. But it’s not easy. The genomes of many vertebrates exceed 1 billion base pairs in length, making it nearly impossible to recreate them without error. more realistic method A small number of labs working on the extinction of endangered species prefer to systematically edit the genomes of extinct animals’ closest living relatives.
Grazelands Rewilding has created a low-tech version of this using a combination of laboratory work and old-fashioned breeding. After mapping the genomes of seven breeds of wild cattle, they used repeated artificial inseminations and cross-breeding to create cattle with DNA similar to aurochs. The current 8th generation Taurus shares over 99% of its genes with the Aurochs. Experts say there are currently 810 tauros left alive. Approximately 350 animals are kept in herds in areas managed for wildlife conservation in Europe, and the rest are in breeding grounds and feedlots in the Netherlands. But they remain tauros, not aurochs, claims Glazelands Rewilding.
Left: Diagram depicting an aurochs bull. Right: Taurus bull.
Adapted from Richmond et al.; rewilding of pasturelands;
At the other end of the spectrum, Texas company Colossal Biosciences is rejecting Glazelands Rewilding’s hesitations about the term. In October, it announced plans to eliminate endangered species. long-billed woodpeckera spectacular red-crowned bird that once lived in the pine forests of the southern United States. We are also working on getting it back. woolly mammoth (extinct 4000 years ago), tasmanian tiger (extinct since 1936), and dodo (Extinct since the late 1600s). The company says the mammoths are helping to fight climate change and keep Siberia’s permafrost intact by trampling and compacting the snow that protects the ground from the bitter cold of winter. The Tasmanian tiger will restore an apex predator to Australia’s hollowed-out forests. And the dodo has such symbolic value that the expression “died as a dodo” will become obsolete. Colossal Biosciences has received a lot of media attention and says it has raised more than $225 million in venture capital funding.
The appeal of De-Extinction is clear. If you can restore it, keystone speciesimprove ecosystem function, excitement About conservation. It also comes with the satisfaction of righting past wrongs. But skeptics are not convinced. They complain that the technology could divert attention and funding from more urgent conservation efforts, create new vectors for pathogens, and make them appear extinct. less threat.
Species are dynamic living organisms that evolve over time. You cannot cut and paste onto an existing animal.
Proponents and detractors have spent a decade debating these issues. But now, a new perspective is attracting attention among scientists. Claire Palmer, professor of environmental philosophy at Texas A&M University, hits the point directly: You are creating something else. ”
The challenge begins with accurately mapping the genomes of extinct species. DNA begins to break down as soon as an animal dies. Genetic blueprints from museum specimens and tissues found in permafrost are constantly fragmented. The probability of complete reproduction is slim. The second problem is that animals have DNA both in the cell nucleus and in the cytoplasm outside the nucleus. This other type of DNA, mitochondrial DNA, is inherited from the mother during pregnancy. Extinct animals do not have mothers of their kind.
Other factors also compound the difficulty. The microbial composition of the surrogate womb will be different than in the past. Baby mammoths and possums do not have siblings and are raised by parents of different species. Thanks to climate change, temperatures will become even warmer. A new set of microorganisms and invertebrates will crawl on its skin. The behavior and social environment that shaped the original species will no longer exist. Extinct animals may be visually similar to missing animals, but they are far from the same.
Aurochs cave etching in Coa Valley, Portugal.
Nature Photo Library / Alamy Stock Photos
Dutch ecologist Ronald Godery, who led the Taurus creation mission, recognized early on that eliminating extinction in an ecologically meaningful way was impossible. international team of scientists published But Godery knew that aurochs were more than just DNA code that could be copied into cows. “The gene pool, population structure, behavior and habitat of millions of animals were equally essential to the project’s success,” he says. Species are dynamic life forms that evolve over time and across continents. You cannot cut and paste onto an existing animal.
Godery is not alone. Ben Novak is chief scientist at the California-based nonprofit Revive and Restore, which is leading a project to wipe out the passenger pigeon from a North Carolina lab. Although Revive & Restore uses the term “de-extinction” on its website, Novak says, “Without a fully cryopreserved genome, no matter how much science advances, we will never be able to actually recover the original extinct species.” cannot be reproduced.” Genetic information is always lost.
Published by Novak, paper in diary gene In 2018, he published his own definition of extinction. His vision is one of “replacement by proxy,” adapting organisms to fulfill the ecological functions of extinct species. The pigeons that Revive & Restore plans to reproduce will be hybrids with genes from both passenger pigeons and fruit pigeons. “Strictly speaking, endangered or extinct doesn’t seem to be the right term,” Novak said. “But it’s a made-up thing.”
“Currently, it is not possible to recreate a species that is 100 percent identical to a species that has disappeared,” the scientist says.
So it turns out that deextinction may be less about creating a Jurassic Park and more about creating a worthy approximation. This follows the thinking of the International Union for Conservation of Nature, which established a task force in 2014 to develop a set of guidelines for eradicating extinction. that last report This term suggests “misleading”. The careful language they coined describes the creation of “ecological substitutes” or “surrogates.”
To let go of the word de-extinction is to let go of the Hollywood buzz a bit, and to abandon the appeal of the idea of reversing extinction. However, there are benefits to refraining from such provocative language. Most importantly, it is more scientifically accurate. “It may be too deceptive, but people are being told they’re getting something they don’t deserve,” said Palmer, the environmental ethicist. When she talks about the extinction of endangered species in class, she puts the word in quotation marks.
It turns out that Colossal Biosciences also recognizes that deextinction means something different than what many people assume. Beth Shapiro, the company’s chief scientist, acknowledged that “it is currently impossible to recreate an extinct species that is 100 percent identical in every respect – genetically, physiologically and behaviorally.” are. Shapiro said the company aims to[bring] Recovering core characteristics of extinct species with the goal of replacing lost ecological interactions in ecosystems. ”
A dodo skeleton opposite a model of an extinct bird at the National Museum of Wales in Cardiff. 1938.
Becker/Stringer
And the company’s ambitions go even further. Because all animals created today have to deal with changing environments and many new challenges, the company looks to past biodiversity to identify endangered species and how they can help species in their current and current environments. She says she sees it as a technology that adds innovation to help people adapt. Future situation. For example, animals may be adapting to cope with heat stress or avoid new diseases associated with a warming climate.
Regardless of what happens with the term endangered species extinction, Palmer believes that restoring species similar to those lost can be a worthy goal. “In some cases, species that no longer exist seem to be needed,” she says. Glazelands Rewilding believes that the tauros’ large weight, jaw shape, and complex social behavior in groups are all ecologically valuable. european landscape evolved Its natural diversity in the presence of wild cattle weighing 2,000 pounds. The quoll-like predator shaped Tasmania’s forest ecosystem. Similarities to extinct animals could help reestablish important relationships between grasses, insects, and herbivores. Recover humanity’s lost encounter with the charismatic beast. It helps combat the ongoing erosion of biodiversity.
The biotech expertise accumulated through the efforts of companies such as Colossal and Revive & Restore may also be important. While Colossal was researching woolly mammoths, vaccine Protects against the herpes virus, which is deadly to young elephants. Dodo efforts led to conservation strategy In Mauritius’s pink pigeons, gene editing to combat inbreeding was the focus. Revive & Restore applies biotechnology to address problems people face. coral, Przewalski’s horseand Narwhal.
In Croatia’s Lika Plain, Portugal’s Core Valley, and Romania’s Danube Delta, small herds of tauros have learned to coexist with wolves and brown bears. the crowd will help restore They grow plants and spread native species through their droppings. This sight is reminiscent of the Paleolithic past. After all, aurochs have been playing this role for thousands of years. But from an ecological perspective, tauros are here to restore landscapes and prepare ecosystems for what’s to come.
complexity generated by ecosystem engineer Like Taurus, it creates stability in the face of change. And regardless of whether someone calls the aurochs “extinct aurochs,” everyone participating in this discussion knows that ecological stability is critical for decades to come. There is.
