First Cloned Dog Is a One-in-a-Thousand Success

Researchers in South Korea have produced the first cloned dog -- a frisky Afghan hound puppy -- in a scientifically daunting feat eagerly anticipated by scientists and pet owners alike.

Snuppy -- short for Seoul National University Puppy -- was grown from an embryo containing DNA from the ear of a male hound selected for his gentle and docile nature, said Woo Suk Hwang, one of the lead researchers.

The black, white and tan puppy, now 3 months old, was the sole survivor among more than 1,000 cloned embryos that were transferred into surrogate mothers.

Cloning experts were impressed that even one healthy dog was created. Even as teams around the world have cloned mice, rabbits, pigs, cows, cats and one horse, the eccentricities of the canine reproductive system have made it exceptionally difficult to add man’s best friend to that list.

Companies that plan to offer dog-cloning services were quick to herald the achievement, published today in the journal Nature.

“This validates one of the premises of our business,” said Ben Carlson, a spokesman for Genetic Savings & Clone Inc. The Sausalito, Calif., company is storing DNA samples from several hundred dogs in anticipation of producing clones for customers as early as next year.

The researchers in South Korea emphasized that their goal was not to reproduce beloved pets.

Hwang said his group’s primary aim was to develop genetically identical laboratory dogs for the study of animal and human diseases.

“With the promise of using a homogenous population of cloned dogs, maladies such as hypertension, diabetes, breast cancer or genetic disorders like congenital cardiac defect can be studied more efficiently,” said Hwang, whose lab was the first to clone human embryos last year.

Scientists have been trying to clone dogs since shortly after the birth of Dolly the sheep, the first animal cloned from an adult, in 1996.

The technique involves harvesting unfertilized eggs from females, removing the genetic material and replacing it with DNA from a donor, usually taken from a skin cell. The manipulated embryo is then implanted into a surrogate mother.

Even as cloning became routine in many species, dogs remained elusive.

“Probably most important is the difficulty in obtaining good-quality eggs,” said Dr. Duane Kraemer, a professor of veterinary physiology at Texas A&M; University, who helped clone the first cat but has not succeeded with dogs.

Female dogs come into heat once or twice a year, providing researchers with few opportunities to extract eggs or implant cloned embryos into surrogate mothers.

Making matters worse, eggs harvested from canine ovaries are not mature enough to be coaxed into pregnancy. Research teams have been testing a variety of methods for ripening the eggs in the laboratory, as can be done with eggs from other species, but have yet to hit upon a reliable method.

The South Korean team allowed the eggs to leave the ovaries and mature for a few days in the body before flushing them out.

That turned out to be an important decision, but it also created a new challenge. By then, the eggs had migrated to the oviduct, a thin tube that carries them to the uterus.

Locating an egg in the oviduct -- and finding a way to retrieve it -- is considerably more difficult than harvesting eggs from an ovary, said Betsy Dresser, senior vice president of research for the Audubon Nature Institute in New Orleans, which uses cloning to help preserve endangered species.

In addition to using improved techniques, the South Korean team also benefited from trial and error.

The researchers transferred 1,095 cloned embryos into 123 surrogate dogs to produce three pregnancies, one of which resulted in a miscarriage.

Snuppy was delivered by caesarian section in late April. A second puppy died of pneumonia 22 days after its birth. The researchers do not think the illness was related to cloning.

Snuppy is healthy and lives in the university’s research facility, Hwang said.

Gerald Schatten, a biomedical researcher at the University of Pittsburgh and a co-author of the study, said the inefficiency of the process suggests that commercial dog cloning for pet owners is still a ways off.

“We transferred 1,095 embryos and got one dog,” said Schatten, who leads the Pittsburgh Development Center, a biology research institute. “If I were an investor and someone came in and said we have a technique that works at 0.09%, I’d say that doesn’t sound like a good investment.”

Companies agree that cloning methods will have to become much more reliable before they can begin delivering puppies to customers.

“We knew that it could be done,” said Philip Damiani, chief scientific officer at Genetic Savings & Clone. “It’s just a matter of trying to figure out the optimal protocol to make this efficient.”

Pet cloning became a reality in 2002, when scientists at Texas A&M; produced a kitten named Carbon Copy. Genetic Savings & Clone, which funded the research, now charges $32,000 for the service.

A Gallup poll conducted in May found that 61% of Americans considered animal cloning morally unacceptable. But it also reported that 35% were comfortable with the idea.

Among them is Peter Lowenstein, an Oakland chiropractor who has already banked DNA from his beloved Sneakers, a 70-pound cross between an Irish wolfhound, Scottish deerhound and Labrador retriever with wiry charcoal hair and yellow eyes.

Sneakers died last year while she was under anesthesia for a routine procedure to investigate a spinal problem.

A vet collected tissue from inside her mouth, her abdomen, and some internal organs and sent them to Genetic Savings & Clone, which preserves them in liquid nitrogen. The company charges $1,395 initially and an annual storage fee of $150 to bank DNA from deceased pets.

“I was so brokenhearted,” Lowenstein said. “If she had lived a good life and just died of old age, I don’t think I would have done it, but it wasn’t her time.”

Though Hwang considers pet cloning frivolous, he said the technology could one day be used to make genetic copies of top-notch guide dogs, search dogs, rescue dogs and other service animals.

The Audubon institute’s Dresser said endangered dog species such as the Ethiopian wolf and the Mexican gray wolf could also benefit from cloning.

With the birth of Snuppy, the next big goal is to clone primates. Monkeys, chimpanzees and humans produce very fragile eggs that are more sensitive to environmental factors such as temperature than eggs from other species, said Damiani of Genetic Savings & Clone.

“When the first monkey is done, that will be a big deal,” Damiani said.

Hwang’s lab has cloned human embryos, but they grew for only five days before being transferred to culture dishes, where they developed into stem cells designed to be used in scientific experiments.

Hwang had no intention of implanting the embryos in surrogate mothers and does not believe they would have survived, in any case.

Beyond the moral and ethical issues of human reproductive cloning, experts think cloned embryos have too many genetic abnormalities to grow into healthy babies.

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Claims and clones

Researchers have cloned a variety of mammals since Dolly the sheep was produced from an adult cell almost a decade ago:

1996: The sheep Dolly is the first mammal cloned from adult cells.

1997: Oregon researchers report that they had cloned monkeys from embryos.

1997: Scientists unveil a Holstein calf cloned from a fetus.

1997: Scottish researchers announce that they created three identical lambs that each

contain the same human gene.

1998: Two calves are born in Tokyo, cloned from adult cow cells.

1998: An international research team announces that it has cloned three generations of laboratory mice.

1998: Scientists clone three female goats.

1998: Researchers in South Korea claim to have created a cloned human embryo, but experts are skeptical.

2000: The British company that helped to clone Dolly is the first to clone pigs.

2001: A clone of a rare breed of Asian ox is born from a cow but dies in two days.

2002: French researchers clone rabbits.

2002: A religious group called the Raelians claim to have produced the first human baby clone.

2003: Scientists in Utah and Idaho clone a baby mule.

2003: Iowa researchers say they cloned a member of an endangered, cattle-like species known as the banteng.

2003: An Italian team announces that it has cloned the first horse.

2003: Scientists announce that they have successfully cloned laboratory rats.

2004: A Sausalito, Calif., company produces the first cloned kitten, which becomes the first cloned pet known to be sold.

Wednesday: South Korean scientists announce that they have cloned the first dog, dubbed Snuppy.

Source: Times research. Compiled by John Jackson