Mammoth Dawn (15 page)

But what would we be willing to call salvation? Even if Church and his colleagues manage to retrofit every passenger pigeon-specific trait into a rock pigeon, say, would the resulting creature truly be a passenger pigeon or just an engineered curiosity? If some do produce a single gastric brooding frog, does that mean they’ve revived the species? If that frog doesn’t have a mate, then it becomes an amphibian version of Celia, and its species is as good as extinct. Would it be enough to keep a population of the frogs in a lab or perhaps in a zoo, where people could gawk at it? Or would it need to be introduced back into the wild to be truly de-extinct?

“The history of putting species back after they’ve gone extinct in the wild is fraught with difficulty,” says conservation biologist Stuart Pimm of Duke University. A huge effort went into restoring the Arabian oryx to the wild, for example. But after the animals were returned to a refuge in central Oman in 1982, poachers wiped almost all of them out. “We had the animals, and we put them back, and the world wasn’t ready,” says Pimm. “Having the species solves only a tiny, tiny part of the problem.”

Critics admonish that the introduction of a now-alien mammoth species could damage the fragile ecosystem of the existing tundra. To this criticism Russian scientist Sergey Zimov replied: “Tundra—that is not an ecosystem. Such systems had not existed on the planet [before the disappearance of the big creatures, the megafauna], and there is nothing to cherish in the tundra. Of course, it would be silly to create a desert instead of the tundra, but if the same site would evolve into a steppe, then it certainly would improve the environment. If deer, foxes, bovines were more abundant, nature would only benefit from this. And people too. However, the danger still exists, of course, you have to be very careful. If it is a revival of the steppes, then, for example, small animals are really dangerous to release without control. As for large herbivores—no danger, as they are very easy to remove again.”

De-extinction advocates are pondering these questions, and most believe they need to be resolved before any major project moves forward. Hank Greely, a leading bioethicist at Stanford University, has taken a keen interest in investigating the ethical and legal implications of de-extinction. And yet for Greely, as for many others, the very fact that science has advanced to the point that such a spectacular feat is possible is a compelling reason to embrace de-extinction, not to shun it.

“What intrigues me is just that it’s really cool,” Greely says. “A saber-toothed cat? It would be neat to see one of those.”

How?

An analogy: the DNA library. For the mammoth carcasses we’ve found, we have many copies of the same book—DNA segments—but each copy has only a page or two left in it. Worse, the pages weren’t numbered. In each case, the blind rub of millennia had ripped out all but a few of the genetic plans.

The trick lies in realizing that each fragment of DNA found was a book with different pages left. Find enough books, compare the pages, stitch and splice and edit … and eventually patch together a complete book.

After all the talk about molecular groups and amino acids, the library analogy
feels
right. Even a congressman can grasp it.

For decades now, biologists have been finding suitable DNA in frozen mammoth bodies. The next step is to recover and, if possible, combine the DNA with similar living animals such as the Asian elephant, closest living relative to mammoths. If scientists can implant a reconstructed mammoth egg, using advanced cloning techniques, an elephant may give birth to some mammoth-related or true mammoth species.

That lies probably decades away. But we can prepare for it in worked-out, useful ways. A consensus has emerged by 2015: 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.

Some scientists are tackling a less daunting challenge: cloning endangered or very recently extinct animals. The San Diego Zoo and the Audubon Center for Research of Endangered Species in New Orleans both maintain “frozen zoos,” where the DNA of a growing number of endangered species is stored in tanks of liquid nitrogen at –320°F.

In 2003, scientists at Advanced Cell Technology used cells stored at the San Diego facility to successfully clone across the species barrier. They created two bantengs, an endangered Southeast Asian ox, by inserting banteng DNA into domestic cow eggs and placing the resulting embryos in ordinary cows as foster-mothers. It worked.

There is talk of using similar methods to clone endangered giant pandas, African bongo antelopes, and Sumatran tigers. Ultimately scientists hope to re-create extinct species like the Pyrenean ibex and the thylacine, or Tasmanian tiger. (The “tiger” is actually a dog. It’s the largest known meat-eating marsupial of modern times. It was a relatively shy, nocturnal creature with the general appearance of a medium-to-large-size dog, except for its stiff tail. The last one in captivity died in 1939.)

The journal
Scientific American
in an editorial condemning de-extinction, pointed out that the technologies involved could have secondary applications, specifically to help species on the verge of extinction regain their genetic diversity, for example the black-footed ferret or the northern white rhino.
Scientific American
thought, though, that such research “should be conducted under the mantle of preserving modern biodiversity rather than conjuring extinct species from the grave.”

Of course, a resurrected species, while being genetically the same as previously living specimens, will not have the same behavior as the real, extinct, thing. The first animal to be brought back will be raised by parents of a different species (the fetus’s host), not the one that died out. So it will have differing mothering techniques and other behaviors we cannot know.

For decades, explorers and scientists have pulled woolly mammoth carcasses from the Siberian tundra and Canada. These preserved soft-tissue remains and DNA of woolly mammoths make possible two methods:

•     First Method:
Cloning, which would involve removal of the DNA-containing the nucleus of an egg cell from a female elephant. Then replace with a nucleus from woolly mammoth tissue. Stimulate that cell into dividing, insert back into the female elephant. The resulting mammoth/elephant calf would have the genes of the woolly mammoth, though its fetal environment would be different. So far, even the most intact mammoths have had little usable DNA because they have degraded in time. There is not yet enough to guide the production of an embryo.

But the egg would have to be definitely complete. The best method of cloning a mammoth, or any other extinct animal, is to recover its complete DNA sequence. For mammoths, the strand is estimated to be more than 4.5 billion base pairs long—and to express this data in flesh and blood.

In 2009 a group at Pennsylvania State University, led by Webb Miller and Stephan C. Schuster, published 70 percent of the mammoth genome, laying out much of the basic data that might be required to make a mammoth.

This publication is a good start. Still, the remaining 30 percent of the genome would have to be recovered and the entire genome resequenced several more times to weed out errors that have crept into the ancient DNA over the centuries as it degraded. Scientists would also have to package the DNA into chromosomes—and at present they don’t even know how many chromosomes the mammoth had. Yet none of these tasks appears insurmountable, especially in light of recent technical advances, such as a new generation of high-speed sequencers and a simple, inexpensive technique for recovering high-quality DNA from mammoth hair. “It’s a simple question of time and money, not of technology anymore,” says Schuster.

Here’s where the African and Asian elephants may be vital. They are the mammoth’s closest relatives in the saga of evolution.

The Penn State team used the African elephant genome as a guide to reassemble the pieces of mammoth DNA they’d recovered from hair samples. But this ancient DNA is far too fragmented to use to create an organism. So one way to make living mammoth genetic material might be to modify elephant chromosomes at each of the estimated 400,000 sites where they differ from the mammoth’s—effectively, rewriting an elephant’s cells into a mammoth’s. If researchers can figure out how mammoth DNA was organized into chromosomes, another strategy would be to synthesize the entire genome from scratch, although so far the largest genome to be synthesized was only a thousandth the size of the mammoth’s.

Once scientists have functional mammoth chromosomes in hand, they could wrap them in a membrane to create an artificial cell nucleus. Then they could follow the approach pioneered in creating Dolly, the sheep cloned in 1996 by scientists at the Roslin Institute in Scotland: Remove the nucleus of an elephant’s egg. Replace it with the rebuilt mammoth nucleus. Electrically stimulate the egg to trigger initial cell division into an embryo. Eventually, transfer the embryo into an elephant’s womb for gestation. Each of these steps has significant question marks. No one knows, for example, just how to build a mammoth nucleus. Harvesting an elephant egg is difficult, and bringing a mammoth fetus to term in an elephant uterus is fraught with uncertainties.

Still, this method may be the best bet. At least it’s systematic.

•     Second Method:
Similar to the first method, but relies on good luck—finding an intact mammoth sperm cell. Take sperm cells from a frozen woolly mammoth carcass. Inject them into an elephant egg cell. The offspring would be an elephant-mammoth hybrid. Repeat, so more hybrids could be used in breeding. Use skills of animal husbandry to ferret out the more mammoth-like hybrids. After several generations of crossbreeding, these hybrids can converge toward an almost pure woolly mammoth. Such bred hybrids could gain notable adaptations. The mammoth genes contain instructions on adaptations to a much colder environment than modern day elephants. Geneticists are currently doing this at Harvard. They have already successfully made changes in the elephant genome with the genes that gave the woolly mammoth its cold-resistance blood, longer hair, and extra layer of fat.

There are problems, of course. Sperm cells of modern mammals remain potent for 15 years, at most, after deep-freezing. Whether mammoth sperm can be viable is unknown. That makes this method iffy.

But early work has begun. An experiment with an Asian elephant and an African elephant produced a live calf, but it died of defects at less than two weeks old. In 2008, a Japanese team found usable DNA in the brains of mice that had been frozen for 16 years. They hope to use similar methods to find usable mammoth DNA. In 2011, Japanese scientists announced plans to clone mammoths within six years.

In 2009 the first extinct animal was cloned back to life—an Iberian wild goat. The clone lived for only seven minutes before dying of lung defects. Efforts continue. The woolly mammoth genome has been mapped, and a complete strand of DNA may be synthesized soon. However, it was reported in March 2014 that blood recovered from a frozen mammoth carcass in 2013 now gives scientists a “high chance” of cloning the woolly mammoth, despite previous troubles.

Ecological work is moving forward, too. A revived woolly mammoth or mammoth-elephant hybrid might find suitable habitat in the tundra and taiga forest ecozones of the Arctic. They may also find refuge in a Pleistocene Park, an experiment by Russian scientist Sergey Zimov. He aims to recreate the mammoth steppe, the woolly mammoth’s former habitat. Indeed, mammoths could recreate the steppe, since they are highly effective in quickly clearing brush and forest, by stripping them away and eating them. That will let grasses colonize the area. No modern arctic large animals can do that.

When?

Given the great advances since the “genetics revolution” of the 1990s, resurrection seems near.

“I laughed when Steven Spielberg said that cloning extinct animals was inevitable,” says Hendrik Poinar of McMaster University, an authority on ancient DNA who served as a scientific consultant for a film about the making of
Jurassic Park
. “But I’m not laughing anymore, at least about mammoths. This is going to happen. It’s just a matter of working out the details.”

Yes, but for how long?

The first method above will take a decade at least, I believe. Maybe two.

The second relies on luck. Several teams are steadily recovering mammoth carcasses across Siberia. If they can find a viable sperm cell, this would be the way to go. It could yield a mammoth in a decade.

So, some hope?

The array of scientists from major institutions that I’ve cited here gives voice to a rising chorus of such adventurers. That such scientists are willing to devote endless hours to this quest—and get funding!—is the most positive aspect of the entire mammoth issue.

To be sure, as the prospect draws nearer, we will see opponents. There always are. Our story “Mammoth Dawn” depicts this.

My money, though, is on the mammoth resurrectionists. They are aided by parallel work from those seeking to bring back the great auk, the Tasmanian tiger, the passenger pigeon. They seek a grander future with more possibilities in it—and not, like many technologies, just for humans.

—Gregory Benford

About the Authors

Kevin J. Anderson has published 130 books, 54 of which have been national or international bestsellers. He has over 23 million copies in print in thirty languages. He is best known for writing numerous novels in the Star Wars, X-Files, and Dune universes, as well as a steampunk fantasy novel,
Clockwork Angels
, with legendary rock group Rush.

His original works include the Saga of Seven Suns series, the Terra Incognita fantasy trilogy, the Saga of Shadows trilogy, and his humorous horror series featuring Dan Shamble, Zombie PI.

He has written comics for DC, Marvel, IDW, Topps, BOOM!, and Wildstorm. He edited numerous anthologies, including the
Five by Five
and
Blood Lite
series. He produced two rock albums from the super-group Roswell Six, featuring stars from legendary groups Kansas, Dream Theater, Saga and Asia, with lyrics written together with his wife Rebecca Moesta. He and Rebecca are the publishers of WordFire Press, with over 200 titles in print and eBook format, from 35 different authors.

Kevin has climbed all 54 mountain peaks in Colorado over 14,000 ft and he just completed hiking the 500 miles of the Colorado Trail. And he also enjoys Colorado microbrews.

Gregory Benford has published over forty books, mostly novels. Nearly all remain in print, some after a quarter of a century. His fiction has won many awards, including the Nebula Award for his novel
Timescape
. A winner of the United Nations Medal for Literature, he is a professor of physics at the University of California, Irvine. He is a Woodrow Wilson Fellow, was Visiting Fellow at Cambridge University, and in 1995 received the Lord Prize for contributions to science. He won the Japan Seiun Award for Dramatic Presentation with his 7-hour series, A Galactic Odyssey. In 2007 he won the Asimov Award for science writing. In 2006 he co-founded Genescient, a biotech company devoted to extending human longevity.

His 1999 analysis of what endures,
Deep Time: How Humanity Communicates Across Millennia
, has been widely read. A fellow of the American Physical Society and a member of the World Academy of Arts and Sciences, he continues his research in both astrophysics and plasma physics and biotech. Time allowing, he continues to write both fiction and nonfiction.