Snuppy (right) is a dead ringer for his father
South Korean scientists have successfully cloned the world's first dog. Man's best friend now joins a long list of animals that have been "duplicated." But what makes this achievement so remarkable is that dogs -- unlike sheep, goats, mice, pigs, or even cats -- have such a complicated reproductive biology that cloning them was thought to be nearly impossible. Now that canines have been conquered, will humans be next?
Prague, 4 August 2005 (RFE/RL) -- Scientists call him Snuppy -- a playful reference to Snoopy, the canine cartoon character much loved by children.
But Snuppy is no toy and he's very much alive. Snuppy stands for Seoul National University Puppy.
Yesterday, South Korean researchers announced that the Afghan hound is the world's first cloned dog.
The puppy was grown from a single cell taken from the ear of a 3-year-old male. That cell was fused with the egg cell of a female dog, whose DNA had been removed by scientists.
The female dog acted as a host for the embryo, passing on no genetic material of her own. After a normal pregnancy, she delivered Snuppy -- a puppy that is a clone of the male hound from whom scientists took the initial ear sample.
The process is similar to cloning techniques used to create Dolly the sheep as well as cloned mice and pigs. But dogs presented scientists with a much bigger challenge. Female dogs ovulate only twice a year, at unpredictable times. Unlike other mammals -- including humans -- female dogs cannot be prompted to produce eggs with hormone injections. It makes collecting eggs for cloning experiments very difficult and the South Korean scientists' achievement all the more impressive.
The head of the research team that produced Snuppy, South Korean Professor Hwang Woo-Suk, told a news conference the point of cloning dogs is to advance our understanding of diseases that affect humans and animals. It is not -- as some may think -- frivolous research aimed at replacing people's deceased pets.
"Our research goal is to produce cloned dogs for studying the disease models, not only for humans, but also for animals," Hwang said.
Dogs share many of the same diseases as humans. This, in part, is a result of centuries of selective breeding.
Just as certain types of dogs have been bred with genes that govern specific characteristics, such as their ability to hunt, they have also become carriers of genes that trigger specific diseases.
"It's quite well-known that some breeds of dog have a tendency to have particular types of disease, like retinal degeneration or arthritis," said Dr. Robin Lovell-Badge of Britain's National Institute For Medical Research in London. "For example, Labrador retrievers often have these problems. Some of these disease genes are clearly very similar to human disease genes. And dogs have been used as models of those human diseases for quite some time."
Cloning different dog breeds could allow scientists to better study specific genes that cause diseases such as arthritis or diabetes and come up with cures applicable to dogs -- and humans, as another member of Dr. Hwang's team, Gerald Schatten, noted.
"All these diseases that we humans also get, wouldn't it be a marvelous thing that our best friends would be the first beneficiaries of stem-cell medicine, and in learning whether it is safe and effective in our [pets], we could know whether it is safe and effective for our loved ones?" Schatten said.
Few would argue with that logic. But as the secret of cloning yet another mammal has been unlocked, others worry that the urge to clone humans may prove to hard to resist.
Hwang's team earlier this year proved that cloning does work with human embryos. But the team limited itself to test-tube experiments, in order to grow stem cells for disease research. The Korean scientists said they had no intention of implanting the embryos in a human being.
Dr. Lovell-Badge said that is wise. He noted that the dog-cloning experiment demonstrates one important reason why it should never be tried with humans.
"First of all, they had to manipulate something like over a thousand eggs and then they transferred those 1,000 eggs or so into 123 female recipient dogs," Lovell-Badge said. "And then they had three pregnancies, one of which failed early on, one of which gave to rise to a puppy but the puppy died after a few weeks. And it was only one that was completely successful and lived, and that's the dog they called Snuppy."
In addition to the wasted eggs and high risks, scientists still continue to debate other controversial aspects of cloning. Chief among them is whether cloned mammals begin life with their internal clocks set at zero, or whether they are born at the age of the cells taken from their original donor.
In other words, it is possible that Snuppy was already three years old at birth -- the same age as the original dog whose cells were used for the experiment? Snuppy, despite being a puppy, might never enjoy his dog childhood, a scenario that if applied to humans would raise a host of ethical issues.
See also:
Fact Box: A Timeline Of Animal Cloning
But Snuppy is no toy and he's very much alive. Snuppy stands for Seoul National University Puppy.
Yesterday, South Korean researchers announced that the Afghan hound is the world's first cloned dog.
The puppy was grown from a single cell taken from the ear of a 3-year-old male. That cell was fused with the egg cell of a female dog, whose DNA had been removed by scientists.
The female dog acted as a host for the embryo, passing on no genetic material of her own. After a normal pregnancy, she delivered Snuppy -- a puppy that is a clone of the male hound from whom scientists took the initial ear sample.
The process is similar to cloning techniques used to create Dolly the sheep as well as cloned mice and pigs. But dogs presented scientists with a much bigger challenge. Female dogs ovulate only twice a year, at unpredictable times. Unlike other mammals -- including humans -- female dogs cannot be prompted to produce eggs with hormone injections. It makes collecting eggs for cloning experiments very difficult and the South Korean scientists' achievement all the more impressive.
The head of the research team that produced Snuppy, South Korean Professor Hwang Woo-Suk, told a news conference the point of cloning dogs is to advance our understanding of diseases that affect humans and animals. It is not -- as some may think -- frivolous research aimed at replacing people's deceased pets.
"Our research goal is to produce cloned dogs for studying the disease models, not only for humans, but also for animals," Hwang said.
Dogs share many of the same diseases as humans. This, in part, is a result of centuries of selective breeding.
Just as certain types of dogs have been bred with genes that govern specific characteristics, such as their ability to hunt, they have also become carriers of genes that trigger specific diseases.
"Our research goal is to produce cloned dogs for studying the disease models, not only for humans, but also for animals." -- Professor Hwang Woo-Suk
"It's quite well-known that some breeds of dog have a tendency to have particular types of disease, like retinal degeneration or arthritis," said Dr. Robin Lovell-Badge of Britain's National Institute For Medical Research in London. "For example, Labrador retrievers often have these problems. Some of these disease genes are clearly very similar to human disease genes. And dogs have been used as models of those human diseases for quite some time."
Cloning different dog breeds could allow scientists to better study specific genes that cause diseases such as arthritis or diabetes and come up with cures applicable to dogs -- and humans, as another member of Dr. Hwang's team, Gerald Schatten, noted.
"All these diseases that we humans also get, wouldn't it be a marvelous thing that our best friends would be the first beneficiaries of stem-cell medicine, and in learning whether it is safe and effective in our [pets], we could know whether it is safe and effective for our loved ones?" Schatten said.
Few would argue with that logic. But as the secret of cloning yet another mammal has been unlocked, others worry that the urge to clone humans may prove to hard to resist.
Hwang's team earlier this year proved that cloning does work with human embryos. But the team limited itself to test-tube experiments, in order to grow stem cells for disease research. The Korean scientists said they had no intention of implanting the embryos in a human being.
Dr. Lovell-Badge said that is wise. He noted that the dog-cloning experiment demonstrates one important reason why it should never be tried with humans.
"First of all, they had to manipulate something like over a thousand eggs and then they transferred those 1,000 eggs or so into 123 female recipient dogs," Lovell-Badge said. "And then they had three pregnancies, one of which failed early on, one of which gave to rise to a puppy but the puppy died after a few weeks. And it was only one that was completely successful and lived, and that's the dog they called Snuppy."
In addition to the wasted eggs and high risks, scientists still continue to debate other controversial aspects of cloning. Chief among them is whether cloned mammals begin life with their internal clocks set at zero, or whether they are born at the age of the cells taken from their original donor.
In other words, it is possible that Snuppy was already three years old at birth -- the same age as the original dog whose cells were used for the experiment? Snuppy, despite being a puppy, might never enjoy his dog childhood, a scenario that if applied to humans would raise a host of ethical issues.
See also:
Fact Box: A Timeline Of Animal Cloning