Scientists in South Korea announced yesterday that they had produced a cloned puppy created from skin cells taken from an adult male Afghan hound.
Parts of the cells were incorporated into canine egg cells to produce more than 1,000 cloned embryos, one of which was carried by a golden labrador acting as a surrogate mother.
Since the arrival of Dolly the sheep in 1997, scientists have cloned many different species, including mice, rats, cows, pigs, rabbits, cats, a mule, horses and a gaur - an endangered ox. But a cloned dog has proved elusive because of the difficulty of maturing canine eggs in a cloning laboratory.
Professor Woo-Suk Hwang of Seoul National University and his colleagues overcame the technical problems and yesterday unveiled an Afghan hound called Snuppy.
Snuppy was born in April and was one of two cloned dog embryos to be delivered alive. The second, born in May, died of pneumonia just three weeks after birth.
The scientists created 1,095 cloned embryos and implanted them into the wombs of 123 surrogates. Yet only three pregnancies were confirmed, one ending in a miscarriage. The low success rate - two puppies from 123 surrogate mothers - underlines the dangerous and haphazard nature of the cloning technique.
Professor Hwang and his colleague Professor Gerald Schatten of the University of Pittsburgh said the study's aim was to investigate the cloning of embryos for producing stem cells rather than to develop a way of reproducing animals or humans. Both said the research was not intended to bring human reproductive cloning any closer, or make it ethical to clone pets.
Professor Schatten said: "We are not in the business of cloning pets. Nuclear transfer [cloning] is an extraordinary tool for scientific and medical research. The dismal success rate of 0.09 per cent reiterates that reproductive cloning is inefficient, unnatural and restricted to scientific and medical research applications."
Professor Hwang said: "Human cloning is unethical and should be banned."
Freda Scott-Park, of the British Veterinary Association, said: "Cloning of animals raises many ethical and moral issues that have still to be properly debated."
DOLLY THE SHEEP
Born in 1996 and unveiled in 1997, Dolly broke new ground by being the first clone of an adult mammal.
CUMULINA THE MOUSE
Born in October 1997 - she died of natural causes in May 2000 after raising two litters of offspring.
NOAH THE GAUR
A gaur is an endangered Asian ox and Noah was the first clone of such a threatened species. However, he died within two days of being born.
CC THE CAT
CC or Copycat, was created from a cell from a female called Rainbow and revealed in February 2002.
PROMETEA THE HORSE
The first cloned horse was born in May 2003. She was in fact a clone of her surrogate mother, using her skin cells and an empty egg from another horse.Reuse content