Creation of first cloned dog represents medical breakthrough, ethical dilemma

August 04, 2005|By Dennis O'Brien | Dennis O'Brien,SUN STAFF

South Korea's pioneering stem cell scientists have once again smashed a biological barrier and reignited a fierce ethical debate, spending three years to produce another cloned animal - a frisky, lovable puppy.

The researchers, led by Hwang Woo Suk, insist that they cloned an Afghan hound only to help find cures for human diseases and improve techniques that make it easier to clone stem cells for use in human therapies.

The team from Seoul National University told reporters yesterday that the dog, named Snuppy in honor of the school, was the lone success in an extensive effort subsidized by the South Korean government.

More than 100 dogs were implanted with more than 1,000 cloned embryos in order to produce a puppy delivered by Caesarean section April 24 from a yellow Labrador surrogate mother. The dog weighed a normal 1 pound 3 ounces.

At the same time they proudly showed off their results, the Koreans took pains to condemn the potential reproductive cloning of humans as "unsafe and inefficient." Human reproductive cloning is banned in South Korea.

Other countries, including the United States, are split over whether to ban human cloning, or cloning of any kind, including the production of stem cells.

Embryonic stem cells are the source of all tissue and are widely believed to have tremendous potential in the treatment of human disease. They can be coaxed to grow into heart, brain or nerve cells that could be used to renew ailing organs.

Last year, Hwang's team created the world's first cloned human embryos, and in May, it created the first embryonic stem cells that genetically match injured or sick patients.

The researchers insisted the dog experiment was aimed at creating a reliable research model for scientists - not at the pet market. Although monkeys are genetically closer to humans and crucial to medical research, Hwang told reporters that cloning a monkey "is technically impossible at the moment."

Although dogs are more difficult to clone than many other animals - in part because females are in heat only twice a year - the scientists said they're worth the trouble.

"Dogs share physiological characteristics with humans," Hwang said. "A lot of diseases that occur in dogs can be directly transferred to humans."

Other experts said the work may bring society a step closer to human reproductive cloning and called for a ban before the technology advances further.

"Successful cloning of an increasing number of species confirms the general impression that it would be possible to clone any mammalian species, including humans," said Ian Wilmut, a reproductive biologist at the University of Edinburgh who produced the first cloned mammal, Dolly the sheep, from an adult cell nearly a decade ago.

Researchers have since cloned cats, goats, cows, mice, pigs, rabbits, horses, deer, mules and gaur (a large wild ox of Southeast Asia). So far, efforts to clone a monkey or another primate with the same techniques have failed, and uncertainties continue about the health and life span of cloned animals.

Dolly died prematurely in 2003 after developing cancer and arthritis.

Wilmut and others complimented Hwang's achievement, reported today in the journal Nature. But they said politicians and scientists face a larger and more delicate issue: how to extend research without crossing the moral boundary of duplicating human life in the lab.

"The ability to use the underlying technology in developing research models and eventually therapies is incredibly promising," said Robert Schenken, president of the American Society for Reproductive Medicine. "However, the paper also points out that in dogs, as in most species, cloning for reproductive purposes is unsafe."

Animal welfare groups criticized the experiment. "This technology could lead to a brave new world of puppy production if it were hijacked by profiteers seeking to use cloning to supply the pet trade," said Wayne Pacelle, head of the Humane Society of the United States.

As with other animal cloning, creating a dog raises a number of ethical issues, said Mildred K. Cho, associate director of the Stanford University Center for Biomedical Ethics. They include whether the animal will have health problems, whether the potential scientific benefits outweigh the risks for the animal, and whether dog cloning is a worthy use of scarce scientific resources.

"Some dogs are used specifically to study human diseases," Cho said. "That could be a valid reason, but I think the issues of animal welfare and the health of the animal still remain."

Savings and Clone

A startup called Genetic Savings & Clone Inc. of Sausalito, Calif., produced a cloned-to-order kitten in late 2004 for a $50,000 fee. The group hopes to commercially clone a dog within a year. But as the Korean researchers learned through extensive trial and error, dogs have unique reproductive systems that make them far more difficult and expensive to clone than many other animals.

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