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At first glance, snuppy seems like a perfectly ordinary 7-month-old Afghan puppy. His black and beige coat, still a dense, cottony cushion of baby fur, has yet to sprout the long silky hairs that distinguish his breed. Like any other puppy, he's eager to please and itching to explore the world around him. The sight of his favorite lamb-flavored snacks or the arrival of a new visitor sends him into a frenzy of excited jumping.

But as the world learned to its astonishment last summer, Snuppy is no ordinary pup. He's a clone, his genes derived not from the egg and sperm of a mother and father but from a single cell taken from the ear of an adult Afghan hound. That makes Snuppy the first dog created by cloning, the still relatively new—and for some, troubling—branch of biotechnology. Other mammals have been cloned, starting with Dolly the sheep back in 1996 and followed by mice, cows, pigs, rabbits, horses and, most recently, cats. But dogs had remained elusive—until now.

Snuppy is the product of a lab in which the painstaking process of cloning has become routine. Years of exasperating experimentation, countless mishaps and dispiriting failures have produced a technique so finely tuned that it can tackle even the most stubborn cloning challenges, such as dogs. And it suggests that pretty much any mammal can be cloned—given enough expertise.

That's the key word. Plenty of labs do mammalian cloning these days, but the group that produced Snuppy is, like the puppy himself, extraordinary. With striking regularity, Woo Suk Hwang and his 45-person team have cranked out one cloning breakthrough after another from his laboratory of veterinary science at Seoul National University in South Korea. In recognition of those feats, his cloning techniques—embodied by a history-making puppy—have been chosen Time's Most Amazing Invention of 2005.

Snuppy was just one of the major steps forward for Hwang during this busy year. He also refined his human-cell-cloning process to yield the first stem cells from patients with diseases, bringing medicine a step closer to the possibility of curing illnesses from Alzheimer's to diabetes with a patient's own rejection-proof tissues. Hwang and his colleagues "are the world leaders at doing this," says Douglas Melton, a co-director of the Harvard Stem Cell Institute.

So how is it that countries like the U.S. are playing follow the leader? Partly, at least, by default. While the Bush Administration has banned the use of federal funding for any research involving cloning—including embryonic stem cells, aside from a short list of "grandfathered" cell lines—South Korea's President Moo Hyun Roh has given unprecedented political, financial and social support to cloning research. Unwilling to squander its huge and potentially lucrative lead, the South Korean government last month created the first stem-cell bank. The World Stem Cell Hub, as it is called, will create some 100 human stem-cell lines under Hwang's direction. These will then be distributed to researchers around the globe, letting them bypass the tricky step of creating the stem cells and move straight to the difficult task of coaxing those cells into tissues that could treat disease.

But funding alone—Hwang intentionally keeps his budget lean, relying primarily on $2 million from the government annually—can't explain such resounding success in a country hardly known for its deep scientific roots. Hwang's theory: "Koreans use metal chopsticks, so I think we have good micromanipulation skills," he says. He's only half kidding: Hwang believes that thanks to years of corralling small grains of rice and other slippery foods with stainless-steel slivers, his researchers are especially well suited to squeezing and injecting individual cells under the microscope using fine instruments. He credits that delicate manipulation of cells as a key to his success in creating the first cloned human embryos and extracting a stable colony of stem cells from them in 2004.

That dexterity is the hallmark of the South Korean technique—that and the lab's nearly round-the-clock, seven-days-a-week schedule. "Stem cells do not know Saturday and Sunday," Hwang says. Encouraged by his success with the notoriously finicky human stem-cell lines, Hwang went to the dogs—a challenge even for a lab the caliber of his. Dogs have a limited breeding period; a female's eggs can be harvested for only a few weeks each year, when she is in heat. In addition, the eggs cannot be easily extracted from the ovaries, as they can with pigs and cows. "We failed so many times to get eggs from many egg-donating dogs," says Hwang. "So I studied and surveyed the reproductive cycle and reached a solution. If we try to get the egg not from the ovary but from the oviduct after ovulation, then maybe we would get good-quality eggs."

Hwang and his team began by doing what scientists do best: observe. They meticulously documented the temperature, hormone levels and vaginal cellular changes of potential canine egg donors through an entire ovulation cycle. On some days, they took readings two or three times a day. That way, they could pinpoint when an egg began its journey from the ovary into the oviduct.

The next steps were similar to the ones used in cloning human cells. First, they gently squeezed out the nucleus of each egg and replaced it with an entire ear cell from an adult dog. Then the egg and its new cargo were electrically stimulated and chemically fused in a series of steps that Hwang developed so that the egg would begin dividing and acting like a growing embryo. But the culture medium in which he had been growing his animal clones—even the one that had worked so well for his human stem-cell lines—turned out to be inhospitable to canine embryos. "It took almost two years to get this specific in vitro culture for the dog clones," Hwang says.

After extracting 1,095 eggs from more than 100 donors and transferring five to 12 embryos to each of 123 carefully chosen surrogates, three dogs, including a Labrador retriever belonging to one of Hwang's students, became pregnant. Two fetuses made it to full term and were born by caesarean section last summer. The first, Snuppy, was born to the retriever and was the only one to survive. (The second puppy died two weeks after birth.) "I had already produced many cloned cows and pigs, but when Snuppy was born, it was different," says Hwang. "When I pulled out the first cloned dog from the surrogate mother's uterus, I was so happy. He was very healthy." Whether he will remain that way isn't as clear. Having created dozens of cloned animals, Hwang admits that they can face a wide range of genetic abnormalities.

Rather than deterring Hwang, however, the setbacks appear to have fueled his curiosity. "If we study and develop our technique more, I expect that we can find some ways to diminish, or reduce the rate of abnormalities in cloned animals," he says. His approach has introduced some level of control and standardization to the somewhat haphazard process of cloning. Even before Snuppy's birth, Hwang had streamlined his process to yield more canine clones from fewer donor eggs.

Hwang's success earlier this year on the human side—in creating patient-specific stem-cell lines—was noteworthy for a similar milestone of efficiency: he was able to coax one stem-cell line from just 10 eggs, a remarkable feat that stunned scientists. "They are far ahead in the second part of the process, in the nuclear transfer of the (adult) cell (to the egg)," says Melton. "They are absolutely professional at doing this."

Although many scientists are excited by Hwang's work, some policymakers and researchers are understandably uncomfortable with it. "Cloning forces us to think about, Are we just a mass of cells and biological processes?" says Dr. Robert Klitzman, a co-director of Columbia University's Center for Bioethics. "Stem cells touch on fundamental questions of who we are, where we come from and where we are going."

As a scientist, Hwang can't afford to wait to answer those deep questions. On its opening day, the World Stem Cell Hub was swarmed with applications from 3,500 patients, some of whom appeared in person, volunteering to become subjects of stem-cell studies. And given how fast the South Koreans have jumped ahead of the pack in cloning, their lead over rivals in other nations is likely to keep growing. "I tell all my research colleagues that I want them to be continuously hungry (for knowledge)," says Hwang. So far, there are no signs that their appetite is anywhere near sated.

• Alice Park/Seoul
• First sheep, now a dog—what next? How a lab in South Korea perfected a cloning technique that is likely to transform medical research around the world