for National Geographic News
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 Afghana 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.
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