The Best American Science and Nature Writing 2014 (48 page)

The event was a melee of scurrying and shouting. The children, ranging from four or five to about twelve years old, proved remarkably gifted hunters. They were eager to hear what I had to say about their discoveries. Torcida translated our talk back and forth, and at the end of the two hours I counted a total of sixty species, belonging to thirty-nine families in thirteen orders.

We found strange insects and arthropods, most very small. There were a lot of Hymenoptera (the order that includes ants, bees, and wasps), Coleoptera (beetles), and Diptera (flies). Though we saw surprisingly few ants per se, one species was identified as a rarely seen driver ant (
Dorylus bequaerti
). We also spotted a few birds, reptiles, amphibians, and one mouse.

To most of the public the word “wildlife” primarily means mammals and birds, which have suffered heavily on Mount Gorongosa. People yearn to see large wild animals, and I am no exception. But wildlife also includes the little things that run the world—the insects and other invertebrates that form the foundation of ecosystems on the land. So Gorongosa did not disappoint me. On the contrary, it fulfilled all the yearnings for adventure and discovery I have felt since my boyhood, when I was the age of my helpers on Mount Gorongosa and was venturing into the forests of Alabama and Florida with a net, spade, and collecting jars.

FROM
National Geographic

 

O
N JULY
30, 2003, a team of Spanish and French scientists reversed time. They brought an animal back from extinction, if only to watch it become extinct again. The animal they revived was a kind of wild goat known as a
bucardo
, or Pyrenean ibex. The bucardo (
Capra pyrenaica pyrenaica
) was a large, handsome creature, reaching up to 220 pounds and sporting long, gently curved horns. For thousands of years it lived high in the Pyrenees, the mountain range that divides France from Spain, where it clambered along cliffs, nibbling on leaves and stems and enduring harsh winters.

Then came the guns. Hunters drove down the bucardo population over several centuries. In 1989 Spanish scientists did a survey and concluded that there were only a dozen or so individuals left. Ten years later a single bucardo remained: a female nicknamed Celia. A team from the Ordesa and Monte Perdido National Park, led by wildlife veterinarian Alberto Fernández-Arias, caught the animal in a trap, clipped a radio collar around her neck, and released her back into the wild. Nine months later the radio collar let out a long, steady beep: the signal that Celia had died. They found her crushed beneath a fallen tree. With her death, the bucardo became officially extinct.

But Celia's cells lived on, preserved in labs in Zaragoza and Madrid. Over the next few years a team of reproductive physiologists led by José Folch injected nuclei from those cells into goat eggs emptied of their own DNA, then implanted the eggs in surrogate mothers. After fifty-seven implantations, only seven animals had become pregnant. And of those seven pregnancies, six ended in miscarriages. But one mother—a hybrid between a Spanish ibex and a goat—carried a clone of Celia to term. Folch and his colleagues performed a cesarean section and delivered the 4.5-pound clone. As Fernández-Arias held the newborn bucardo in his arms, he could see that she was struggling to take in air, her tongue jutting grotesquely out of her mouth. Despite the efforts to help her breathe, after a mere ten minutes Celia's clone died. A necropsy later revealed that one of her lungs had grown a gigantic extra lobe as solid as a piece of liver. There was nothing anyone could have done.

The dodo and the great auk, the thylacine and the Chinese river dolphin, the passenger pigeon and the imperial woodpecker—the bucardo is only one in the long list of animals humans have driven to extinction, sometimes deliberately. And with many more species now endangered, the bucardo will have much more company in the years to come. Fernández-Arias belongs to a small but passionate group of researchers who believe that cloning can help reverse that trend.

The notion of bringing vanished species back to life—some call it de-extinction—has hovered at the boundary between reality and science fiction for more than two decades, ever since the novelist Michael Crichton unleashed the dinosaurs of
Jurassic Park
on the world. For most of that time the science of de-extinction has lagged far behind the fantasy. Celia's clone is the closest that anyone has gotten to true de-extinction. Since witnessing those fleeting minutes of the clone's life, Fernández-Arias, now the head of the Aragon government's Hunting, Fishing, and Wetlands department, has been waiting for the moment when science would finally catch up, and humans might gain the ability to bring back an animal they had driven extinct.

“We are at that moment,” he told me.

I met Fernández-Arias last autumn at a closed-session scientific meeting at the National Geographic Society's headquarters in Washington, DC. For the first time in history a group of geneticists, wildlife biologists, conservationists, and ethicists had gathered to discuss the possibility of de-extinction. Could it be done? Should it be done? One by one, they stood up to present remarkable advances in manipulating stem cells, in recovering ancient DNA, in reconstructing lost genomes. As the meeting unfolded, the scientists became increasingly excited. A consensus was emerging: de-extinction is now within reach.

“It's gone very much further, very much more rapidly than anyone ever would've imagined,” says Ross MacPhee, a curator of mammalogy at the American Museum of Natural History in New York. “What we really need to think about is why we would want to do this in the first place, to actually bring back a species.”

In
Jurassic Park
, dinosaurs are resurrected for their entertainment value. The disastrous consequences that follow have cast a shadow over the notion of de-extinction, at least in the popular imagination. But people tend to forget that
Jurassic Park
was pure fantasy. In reality the only species we can hope to revive now are those that died within the past few tens of thousands of years and left behind remains that harbor intact cells or, at the very least, enough ancient DNA to reconstruct the creature's genome. Because of the natural rates of decay, we can never hope to retrieve the full genome of
Tyrannosaurus rex
, which vanished about 65 million years ago. The species theoretically capable of being revived all disappeared while humanity was rapidly climbing toward world domination. And especially in recent years we humans were the ones who wiped them out, by hunting them, destroying their habitats, or spreading diseases. This suggests another reason for bringing them back.

“If we're talking about species we drove extinct, then I think we have an obligation to try to do this,” says Michael Archer, a paleontologist at the University of New South Wales who has championed de-extinction for years. Some people protest that reviving a species that no longer exists amounts to playing God. Archer scoffs at the notion. “I think we played God when we exterminated these animals.”

Other scientists who favor de-extinction argue that there will be concrete benefits. Biological diversity is a storehouse of natural invention. Most pharmaceutical drugs, for example, were not invented from scratch—they were derived from natural compounds found in wild plant species, which are also vulnerable to extinction. Some extinct animals also performed vital services in their ecosystems, which might benefit from their return. Siberia, for example, was home 12,000 years ago to mammoths and other big grazing mammals. Back then, the landscape was not moss-dominated tundra but grassy steppes. Sergey Zimov, a Russian ecologist and director of the Northeast Science Station in Cherskiy in the Republic of Sakha, has long argued that this was no coincidence: the mammoths and numerous herbivores maintained the grassland by breaking up the soil and fertilizing it with their manure. Once they were gone, moss took over and transformed the grassland into less productive tundra.

In recent years Zimov has tried to turn back time on the tundra by bringing horses, muskoxen, and other big mammals to a region of Siberia he calls Pleistocene Park. And he would be happy to have woolly mammoths roam free there. “But only my grandchildren will see them,” he says. “A mouse breeds very fast. Mammoths breed very slow. Be prepared to wait.”

 

When Fernández-Arias first tried to bring back the bucardo ten years ago, the tools at his disposal were, in hindsight, woefully crude. It had been only seven years since the birth of Dolly the sheep, the first cloned mammal. In those early days scientists would clone an animal by taking one of its cells and inserting its DNA into an egg that had been emptied of its own genetic material. An electric shock was enough to get the egg to start dividing, after which the scientists would place the developing embryo in a surrogate mother. The vast majority of those pregnancies failed, and the few animals that were born were often beset with health problems.

Over the past decade scientists have improved their success with cloning animals, shifting the technology from high-risk science to workaday business. Researchers have also developed the ability to induce adult animal cells to return to an embryo-like state. These can be coaxed to develop into any type of cell—including eggs or sperm. The eggs can then be further manipulated to develop into full-fledged embryos.

Such technical sleights of hand make it far easier to conjure a vanished species back to life. Scientists and explorers have been talking for decades about bringing back the mammoth. Their first—and so far only—achievement was to find well-preserved mammoths in the Siberian tundra. Now, armed with the new cloning technologies, researchers at the Sooam Biotech Research Foundation in Seoul have teamed up with mammoth experts from North-Eastern Federal University in the Siberian city of Yakutsk. Last summer they traveled up the Yana River, drilling tunnels into the frozen cliffs along the river with giant hoses. In one of those tunnels they found chunks of mammoth tissue, including bone marrow, hair, skin, and fat. The tissue is now in Seoul, where the Sooam scientists are examining it.

“If we dream about it, the ideal case would be finding a viable cell, a cell that's alive,” says Sooam's Insung Hwang, who organized the Yana River expedition. If the Sooam researchers do find such a cell, they could coax it to produce millions of cells. These could be reprogrammed to grow into embryos, which could then be implanted in surrogate elephants, the mammoth's closest living relatives.

Most scientists doubt that any living cell could have survived freezing on the open tundra. But Hwang and his colleagues have a Plan B: capture an intact nucleus of a mammoth cell, which is far more likely to have been preserved than the cell itself. Cloning a mammoth from nothing but an intact nucleus, however, will be a lot trickier. The Sooam researchers will need to transfer the nucleus into an elephant egg that has had its own nucleus removed. This will require harvesting eggs from an elephant—a feat no one has yet accomplished. If the DNA inside the nucleus is well preserved enough to take control of the egg, it just might start dividing into a mammoth embryo. If the scientists can get past that hurdle, they still have the formidable task of transplanting the embryo into an elephant's womb. Then, as Zimov cautions, they will need patience. If all goes well, it will still be almost two years before they can see if the elephant will give birth to a healthy mammoth.

“The thing that I always say is, if you don't try, how would you know that it's impossible?” says Hwang.

 

In 1813, while traveling along the Ohio River from Hardensburgh to Louisville, John James Audubon witnessed one of the most miraculous natural phenomena of his time: a flock of passenger pigeons (
Ectopistes migratorius
) blanketing the sky. “The air was literally filled with Pigeons,” he later wrote. “The light of noon-day was obscured as by an eclipse, the dung fell in spots, not unlike melting flakes of snow; and the continued buzz of wings had a tendency to lull my senses to repose.”

When Audubon reached Louisville before sunset, the pigeons were still passing overhead—and continued to do so for the next three days. “The people were all in arms,” wrote Audubon. “The banks of the Ohio were crowded with men and boys, incessantly shooting at the pilgrims . . . Multitudes were thus destroyed.”

In 1813 it would have been hard to imagine a species less likely to become extinct. Yet by the end of the century the red-breasted passenger pigeon was in catastrophic decline, the forests it depended upon shrinking, and its numbers dwindling from relentless hunting. In 1900 the last confirmed wild bird was shot by a boy with a BB gun. Fourteen years later, just a century and a year after Audubon marveled at their abundance, the one remaining captive passenger pigeon, a female named Martha, died at the Cincinnati Zoo.

The writer and environmentalist Stewart Brand, best known for founding the
Whole Earth Catalog
in the late 1960s, grew up in Illinois hiking in forests that just a few decades before had been aroar with the sound of the passenger pigeons' wings. “Its habitat was my habitat,” he says. Two years ago Brand and his wife, Ryan Phelan, founder of the genetic testing company DNA Direct, began to wonder if it might be possible to bring the species back to life. One night over dinner with the Harvard biologist George Church, a master at manipulating DNA, they discovered that he was thinking along the same lines.

Church knew that standard cloning methods wouldn't work, since bird embryos develop inside shells, and no museum specimen of the passenger pigeon (including Martha herself, now in the Smithsonian) would likely contain a fully intact, functional genome. But he could envision a different way of re-creating the bird. Preserved specimens contain fragments of DNA. By piecing together the fragments, scientists can now read the roughly one billion letters in the passenger pigeon genome. Church can't yet synthesize an entire animal genome from scratch, but he has invented technology that allows him to make sizable chunks of DNA of any sequence he wants. He could theoretically manufacture genes for passenger pigeon traits—a gene for its long tail, for example—and splice them into the genome of a stem cell from a common rock pigeon.