Scientists ‘immortalize’ world’s first cloned dog Snuppy, the next generation
Snuppy, the world’s first cloned dog, may live in perpetuity.
Scientists have announced the birth of three clones of Snuppy, the Afghan hound who died in April 2015, just 13 days after celebrating his 10th birthday.
To “immortalize” the milestone achievement of cloning a canine, South Korean scientists recloned Snuppy using fat-derived stem cells taken from the hound when he was five years old.
“Three healthy reclones of Snuppy are alive, and as with Snuppy we do not anticipate that the reclones will go through an accelerated rate of aging or will be more prone to develop diseases than naturally bred animals,” the team wrote in Scientific Reports, a journal from the publishers of Nature.
Clones’ health has long been a concern, but the scientists said both Snuppy and Tai, Snuppy’s cell donor, were generally healthy until both developed cancer, from which both succumbed at the ages of 10 and 12 — close to the average lifespan of Afghan hounds.
The second generation of Snuppy clones, they added, will contribute to a “new era” in the study of the health and longevity of cloned animals.
However, “we do not imagine using these technologies for cloning humans,” said co-author CheMyong Jay Ko, of the University of Illinois.
Attempting to clone humans remains illegal, and bioethicist Arthur Caplan argues that the “battle over humans” is going to be more about genetic engineering, and not trying to make Xerox copies of us.
“What we’ll see is more attempts to engineer humans” through gene-editing techniques like CRISPR, he said.
Snuppy (short for Seoul National University puppy, where he was born) was created using somatic cell nuclear transfer, the same technique that produced Dolly the sheep in 1997.
The procedure involves creating an embryo by using a nucleus that’s been removed from a somatic cell — any cell other than a reproductive cell — and transferring it into an unfertilized egg that has been stripped of its own nucleus.
Before Snuppy’s birth in 2005, much debate had been made over whether clones could be expected to grow normally and live healthy, reproductive lives. Dolly, for example, underwent numerous treatments for osteoarthritis before dying in 2003 of severe arthritis and a lung disease. She was just six years old, half the normal life expectancy for a Finn Dorset sheep.
Birth defects have also been reported in some cloned puppies, the researchers wrote in Scientific Reports. However, other cloned dogs have been born without defects and reproduced successfully.
“Animal cloning has gained popularity as a method to produce genetically identical animals or superior animals for research or industrial uses,” they wrote. It’s also big business: Last year design queen Diane Von Furstenberg and media billionaire Barry Diller cloned his beloved Jack Russell terrier into two new puppies for a reported US$100,000.
To answer whether cloned canines aged more rapidly, the researchers compared the longevity of Snuppy and his somatic cell donor, Tai, a male Afghan hound.
Tai was euthanized at his owner’s request when he was 12 after he was diagnosed with hemangiosarcoma, a kind of cancer that occurs almost exclusively in dogs.
Snuppy, on the other hand, died while being treated for T-cell lymphoma when he was 10.
Cancer is common in dogs of all breeds, including Afghan hounds, which have a mortality rate from cancer of 31 per cent.
Snuppy’s clones were created from a special kind of stem cells called mesenchymal cells that can differentiate into several types of cells.
The stem cells were taken from his belly fat when he was five, and frozen. Recently, they were thawed, grown in culture and then injected into enucleated eggs (an egg that has had its own nucleus removed) taken from female donors. The resulting cloned embryos were transferred into surrogate female dogs.
A total of 94 retrofitted embryos were transferred. Four clones were born by caesarean section, however one died four days after birth from severe diarrhea.
The surviving three, which are now about a year old, “will be closely watched. Almost every aspect of their life will be measured — their disease development, their immune system and growth and metabolism,” Ko said.
Snuppy’s clones might also provide insights into the development of cancer and other diseases, he said.