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Dog Cloned by South Korean Scientists

Maryann Mott
for National Geographic News
August 3, 2005
 
South Korean scientists at Seoul National University's College of Veterinary Medicine have beaten a U.S. company in the race to produce the world's first successful dog clone (see photo gallery).

The male Afghan hound puppy, named Snuppy (short for Seoul National University puppy), was born on April 24. A second dog clone died of pneumonia shortly after it was born in May.

Both were created by somatic-cell nuclear transfer, the method that produced Dolly the sheep, the first mammal successfully cloned. Somatic cells are cells other than sperm or egg cells.

This method of cloning involves taking the nucleus from a somatic cell and transplanting it into an egg cell that has been stripped of its own nucleus. In the case of Snuppy, the nucleus of an ear-skin cell from an adult male Afghan hound was transferred to an emptied egg cell of a yellow Labrador retriever. Snuppy is genetically identical to the Afghan—a clone.

The researchers admit, though, that the efficiency of dog cloning is still low. The two puppies were the result of 123 embryo transfers, leading to just three pregnancies, one of which miscarried. A paper on the work appears today in the journal Nature.

Lead researcher Woo-Suk Hwang believes dogs provide a good model for understanding human diseases, some of which afflict both species.

"Using a homogenous population of cloned dogs, maladies such as hypertension, diabetes, [and] breast cancer or genetic disorders, like congenital cardiac defect, can be studied more efficiently," he explained.

Hwang began his cloning career in the late 1990s to help farmers increase profits. He has had a number of successes, including producing cows resistant to bovine spongiform encephalopathy (BSE), or mad cow disease.

He and his team have also worked with human cells. They gained worldwide attention last year when they cloned human embryonic cells capable of yielding viable stem cells that could one day be used to treat diseases such as diabetes, Alzheimer's, and Parkinson's.

Unique Coat Color

As for Snuppy, Hwang said the dog will be kept in the laboratory to monitor behavioral differences with his three-year-old genetic donor, named Tai. The donor dog was chosen for his gentle nature and unique coat color.

Cloning by nuclear transfer is nothing new. The technique was first reported in frogs in 1952. Since then a barnyard's worth of animals has been duplicated, including pigs, goats, mules, horses, and rats. It is believed that the method could also be used to clone humans.

Cloning man's best friend, though, has proven more difficult than cloning farm animals. The researchers said canine eggs are hard to work with, because they are released from the ovary earlier than in other mammal species.

The project took the research team less than three years—a fast accomplishment, considering that the Genetic Savings and Clone company, has struggled to duplicate a dog, named Missy, since 1997.

"Although we had hoped to be first to produce a cloned dog," the Sausolito, California-based company said in a written statement. "Most of our research is geared toward development of the next-generation technologies required for commercialization, especially high-throughput ova assessment and maturation [in other words, more succesful clones from fewer eggs], which the South Koreans cite as a key bottleneck to canine cloning."

The company believes it will produce a canine clone this year and that the method it now uses, called chromatin transfer, will result in better efficiencies and health outcomes than the conventional nuclear-transfer method used by the South Korean scientists.

The multimillion-dollar Genetic Savings and Clone project is funded by Missy's owner, Arizona entrepreneur John Sperling. The husky mix died in 2002, but her tissue samples have been saved for cloning.

While dogs have been elusive for Genetic Savings and Clone, cats are a different story. In 2002 the company produced the first copied cat and last year began offering its service to the public.

$32,000 to Clone a Cat

So far, five cats have been cloned commercially. The current cost for the service is U.S. $32,000.

Hwang says the university has no plans to produce dogs for individual owners. Instead, his future research plans involve treating hereditary disorders in dogs as well as studying human genetic diseases and certain canine diseases.

"Eventually, our cloning technology may be utilized for cloning service animals, such as guide dogs, and search-and-rescue dogs," he said. "Perhaps this cloning technology could even be applied to the preservation of endangered species."

Animal Suffering

News of the bioengineering breakthrough had some people growling.

Crystal Miller-Spiegel is a senior policy analyst for the American Anti-Vivisection Society (AAVS), based in Pennsylvania. She voiced concerns about the welfare of animals used in cloning experiments, which involve multiple invasive procedures.

"Animal cloning is consistently inefficient and leads to grave animal suffering," she said.

Earlier this year AAVS tried to get a bill passed in California to ban the sale of cloned and genetically modified pets.

The organization also petitioned the U.S. Department of Agriculture to require cloning companies to be licensed, like it does research laboratories. Licensing would make cloning companies adhere to federal standards of humane care and treatment of animals, as well as require periodic inspections.

Both attempts failed.

The California bill, however, is still active and will be reconsidered in the next legislative session, Miller-Spiegel said. If passed, it will be the first of its kind in the United States.

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