Snuppy pictured with his surrogate mother
THE LONG-CHERISHED dream that Man can reproduce his best friend has become a reality when South Korean scientists announced last week they had created the world's first cloned dog.
Dr Woo-Suk Hwang and his team of researchers at Seoul National University made world headlines earlier this year when they created human stem cells with a patient's specific genetic material, derived through cloned embryos, giving rise to the usual bout of headlines about ‘Frankenstein-style science’.
Now the South Koreans have secured their place as leaders in the cloning field by creating Snuppy, the first dog cloned from adult cells by somatic nuclear cell transfer. This is the same technique used to create Dolly the sheep, recognised as the world's first cloned mammal, and many other animals including pigs, cows, horses, rabbits, rats and mice.
Dr Hwang said the breakthrough in cloning dogs may advance work on combating diseases by therapeutic cloning with stem cells.
"Our research goal is to produce cloned dogs for (studying) the disease models, not only for humans, but also for animals," Hwang told a press conference.
Lee Beyong Chun, the first author of the dog cloning paper, published in ‘Nature’ magazine, says he and his colleagues began the process on Aug. 2, 2002, supported by a grant from the South Korean government. Working non-stop and using over 1,000 dog eggs, they finally ended up with an Afghan hound puppy that is a clone of an adult male Afghan.
Snuppy, an acronym for Seoul National University puppy, where Hwang's lab is located, is a male born by caesarean section weighing 530 grams (19 ounces) on April 24th after a normal, full-term pregnancy in a yellow Labrador surrogate mother.
The second puppy, identified as NT-2, weighed in at 550 grams (19.4 ounces) but died 22 days later from pneumonia. A post-mortem exam showed there were no anatomical problems with the dog that died.
Nuclear cell transfer is a notoriously difficult method of cloning. Dolly the sheep was the only viable embryo to survive out of 600 fertilized eggs. In the case of Snuppy, a total of 1,095 reconstructed embryos were transferred into 123 surrogate mother bitches to create the two dogs -- an efficiency rate of 1.6 percent.
Both puppies were created from an adult skin cell taken from a male Afghan hound using somatic cell nuclear transfer. The Afghan breed was selected mainly for its size and striking appearance, researchers said.
It has taken scientists longer to clone a dog than other animals because of the difficulty in producing mature, unfertilised canine eggs in the laboratory.
Unlike other mammals, dog eggs are released earlier from the ovary than in other species. Instead of maturing the eggs in the lab, the researchers overcame the problem by collecting mature eggs from the dogs.
The egg's genetic material was removed and replaced with the nucleus of the skin cell from a male Afghan hound, then fused to create an embryo, which was implanted into a surrogate mother at the correct time to coincide with the embryo development.
Some observers cautioned there are many unresolved ethical questions about where the science may lead.
"Canine cloning runs contrary to the Kennel Club's objective 'To promote in every way the general improvement of dogs'," Phil Buckley, spokesman for the Kennel Club commented. "Cloning cannot be used to make improvements because the technique simply produces genetic replicas of existing dogs.
"Also, will these cloned dogs end up being used in the laboratory? That opens a whole new can of worms."
Dr Freda Scott-Park, President Elect of the British Veterinary Association, is concerned about the likely reaction of dog lovers.
"This report demonstrates just how fast the world of genetic manipulation is moving and no one should underestimate the far-reaching consequences of this work," she said.
"Sadly however, the media interest is likely to attract pet owners keen to re-create their much loved pets.
"No one can deny that techniques that advance our understanding of diseases and their therapy are to be encouraged. But cloning of animals raises many ethical and moral issues that have still to be properly debated within the profession."
However, another member of the cloning team, Dr Gerald Schatten from the University of Pittsburgh School of Medicine, US, said the South Korean team are not in the business of cloning pets.
"The overall objective of this programme is to learn about the root causes of diseases," commented Dr Schatten. "We believe it is possible, if you can responsibly develop the ability to derive stem cells from cloned dog embryos, that our very best friends may turn out to be the first beneficiaries of stem cell medicine.
"And as we treat naturally occurring diseases in dogs, we'll learn about whether it is effective in our pets and we'll also learn whether it's safe and effective for our loved ones."
Koreans win the race
The fact that the South Koreans won the cloning equivalent of the space race and thus became the first to clone a dog was a bitter blow to the leading American team of Genetic Savings & Clone, who created ‘CC’ the world’s first cloned cat in 2001, and a have since gone on to produce a number of other cloned cats. GSC are based at Texas A&M University, and in 1997 launched a high profile, $4 million dog-cloning project backed by billionaire John Sperling. The ‘Missyplicity project’ was aimed at cloning Sperling’s favourite canine, a crossbred named Missy.
Genetic Savings issued a short and rather terse press release on the Korean first, congratulating its rivals but attributing their win partly to the "greater availability" of dogs for research in South Korea, where animal-protection groups have little sway. "We expect to produce our own canine clones in the near future," it added.
Texas A&M cloning expert Duane Kraemer, revealed that the GSC group nearly succeeded in cloning a dog three years ago. One of its Missy clones seemed perfectly healthy in utero but was stillborn, he said.
Dog welfare charity condemns dog cloning
Following the announcement of the world's first cloned dog, Dogs Trust, the UK's largest dog welfare charity, has condemned the practice of dog cloning as unnecessary and cruel.
The charity says there is no benefit in this expensive procedure to dogs, and that, in addition to the ethical issues, there are a number of associated health and welfare concerns.
In this recent case it took over 100 attempts to achieve just two pregnancies, one resulted in miscarriage and another puppy died at just a few weeks of age. The charity says is cannot be justified, because of the likely pain or distress suffered by the bitches as a result of the unnecessary procedure.
Chris Laurence, Veterinary Director of Dogs Trust commented: "This is just
absurd at a time when thousands of dogs are abandoned, unwanted and are put to sleep every year.”
Mr Laurence added: "We are yet to learn if there are any long term risks associated with this procedure. Cloned dogs may be congenitally abnormal or suffer from problems that can cause a shortened lifespan and may lead to abuse or abandonment of the dog. There are other means of improving the genetic health of dogs which cause far fewer welfare problems."
The charity is also concerned that owners of cloned dogs may have unrealistic expectations while trying to create a replica of an existing pet. It is highly unlikely that the temperament of a cloned animal will be identical to the donor as this is linked to early socialisation and other environmental factors; some estimates state that heredity contributes to only 20% of behaviour, with the remainder learnt as a juvenile. Therefore, if people believe through cloning they will achieve a copy of their pet, this is unlikely to happen.