Noah's New Ark

By Maryann Bird/London

Noah's Ark has set sail again, crossing stormy scientific waters and buffeted by winds of controversy. Unlike the Old Testament vessel, however, today's metaphorical ark is not carrying threatened animals two by two to safety. Rather, if it lives up to its billing, it could produce potentially unlimited numbers of endangered creatures.

In the updated story, though, Noah is not the skipper of the rescue project. Instead, it's the name given in advance to the clone of a dead gaur, an endangered wild ox found in India, Bangladesh and Southeast Asia. The new Noah is expected to be born any day now to Bessie, a cow living on a farm near Sioux City, Iowa. Cows have given birth to gaurs before, but this is the first time that one animal species is acting as surrogate mother to a clone--an exact genetic duplicate--of a different species. "The gaur is developing well," says Emily Poe, a spokeswoman for Advanced Cell Technologies. A small biotechnology company based in Worcester, Mass., ACT is using a novel cross-species nuclear-transfer technique that could usher in what it sees as a new era in conservation.

Bessie's ultrasound tests may look good, but is the concept itself a sound one? Robert Lanza, ACT's vice president of medical and scientific development, says the technique is not a panacea but "presents exciting possibilities" that may help rescue endangered species and perhaps even reverse extinctions. Other scientists aren't so sure. They argue that such high-tech approaches are unlikely to make a significant contribution to the support of vulnerable species, especially if their habitats have been destroyed.

Still, if Bessie's little gaur is delivered safely, the birth will come as a boost to many biologists in the U.S. and Europe who are engaged in a range of "assisted reproduction" conservation strategies. These include artificial insemination and in vitro fertilization. In particular, though, Noah's arrival will hearten the scientists at ACT, who recently signed a deal with Spanish officials to attempt to clone the bucardo, an extinct mountain goat native to the Pyrenees. The last bucardo died a year ago, struck by a falling tree in its final habitat, northern Spain's Ordesa National Park. Scientists had already preserved a quantity of its cells, and ACT hopes to transfer them into other goats' eggs, perhaps later this year.

The cloning technique used with Bessie--the only cow in the experiment to carry an embryo into late pregnancy--is a variation of the procedure that created Dolly the sheep, the world's first cloned mammal. A needle is jabbed through an egg's protective layer and used to remove the egg's nucleus, containing most of a cell's genetic material. A second needle is used to inject a whole cell under the egg's outer layer. To complete the process, an electrical current fuses the new cell to the egg. The embryo starts to divide until, within days, the mass of cells grows to about 100 and is big enough to be implanted in the surrogate mother's uterus.

The creation of Noah began with the fusing of skin cells from a male gaur and 692 cow eggs. Just 81 grew into blastocysts (clumps of cells suitable for implantation), and 42 of those were inserted into 32 cows, of which eight became pregnant. Two of the fetuses were later removed for study, while five cows sustained spontaneous abortions. Only Bessie and Noah are left.

As ACT scientists await the clone's birth, other wildlife researchers express doubts about the project's conservation claims and think the wrong message is being sent. "We do not believe that cloning has any relevance to the routine management and conservation of endangered species," says David Wildt, a senior scientist at the Smithsonian Institution's Conservation and Research Center in Front Royal, Va. Instead, Wildt favors low-tech methods, like the artificial insemination used to breed the endangered black-footed ferret, which is now being reintroduced to the American West. "Our laboratory works all over the world with the rarest of species," he says, "and not once have I ever heard a real wildlife manager or wildlife scientist say, 'Gee, we must attempt to save this species using cloning.'"

To William Holt, a research fellow at the Institute of Zoology in London, the best approach is to learn more about species' reproductive systems and the social conditions that can make animals want to breed naturally. "If you know those things, you can improve success rates a lot without doing anything invasive." Where cloning technology may be useful, Holt allows, is "where the species is down to 50 or so. You could sample cells from all of them. You could re-create all of these 50 individuals. You've still got the genetic variability that is important." Failing to do so, he suggests, could result in populations that lack the genetic diversity to fight off disease, setting the creatures up for a second extinction. Suitable habitats are also necessary. "You've got to ask, Are we helping these animals into the future?"

Helping animals into the future is a priority for the world's wildlife researchers as an ever growing number of species become imperiled each year. Oliver Ryder, a geneticist at the San Diego Zoo's Center for Reproduction of Endangered Species, is the driving force behind a 25-year effort to assemble a bank of frozen dna, eggs and sperm from endangered species. Under his direction, the frozen zoo now has living cells from 5,400 animals spanning more than 400 species and subspecies, cultured and frozen in liquid nitrogen.

One missing creature is often on Ryder's mind. "Could you take a cell from a Morro Bay kangaroo rat and bring it back, and would it be the same?" he asks. "There are a lot of questions, but we don't have that option now because nobody saved the cells" while lab work was being conducted on the rodent in the 1970s. "The future will want to know about these species, and the lingua franca of biology is increasingly going to be genomic information. If nobody saves the DNA of these samples, it's going to be a very fragmented picture." There is also a present-day, practical side. By providing vital clues to the mingling of subspecies and the types of environment they require, genetic data can help zoologists care for endangered animals in captivity.

Using science to save vanishing species is becoming a global pursuit. Robert Mauget and colleagues at France's National Museum of Natural History, which includes four zoo parks, recently became the first to produce deer embryos in vitro. The technique--incorporating frozen semen and oocytes, or developing egg cells--is expected to be applied later this year to rare and endangered deer species, with more common types acting as surrogate mothers. The French are also talking with colleagues in Uzbekistan and Kazakhstan about how they may help rebuild populations of Bactrian (Bukharian) deer in Central Asia. "Basically, we're hoping to give them our recipe," says Mauget.

At Austria's Salzburg Zoo, scientists are developing a recipe they hope will lead to the first production of white rhinos through artificial insemination. Franz Schwarzenberger of Vienna's University of Veterinary Medicine believes success with the tricky technique could help save even more endangered rhino species, such as the northern white. "It may be possible to collect semen in the wild and inseminate animals in captivity," he says. "This kind of assisted reproduction offers us a chance to improve the gene pool of the captive population without taking resources from the wild."

After years of watching one species after another become extinct, researchers are sounding optimistic. "We don't have the right to do nothing," says Mauget, who predicts that interzoo exchanges of sperm, oocytes and embryos will develop rapidly. "Instead of shipping our animals from one zoo to another, we'll be sending sperm to the four corners of the earth." Meanwhile, in a corner of Iowa, another kind of delivery is awaited.

--Reported by Edward Barnes/New York, Dan Cray/Los Angeles, Tala Skari/Paris and Jane Walker/Madrid

With reporting by Edward Barnes/New York, Dan Cray/Los Angeles, Tala Skari/Paris and Jane Walker/Madrid