LONDON: The shock of the new became the shock of the old on Friday when Dolly, the world’s most closely watched sheep, hobbled back into the limelight, aged before her time. Dolly stunned the world in 1997 when she was revealed, the first animal to be cloned from an adult cell. Then and since, her creators, the Roslin Institute near Edinburgh, in Scotland, stressed that though her origins were extraordinary, she was in other respects a healthy, normal sheep.

On Friday, at the age of five-and-a-half, it was announced that she had succumbed to arthritis - a condition extremely rare in normal sheep of that age. With sheep life expectancy somewhere between 10 and 15, Dolly is no spring lamb. But the realisation that she suffers from arthritis brings her close enough to mutton to cast fresh doubts over the entire controversial field of cloning and spur the anti-cloning lobby to a new round of jeering. Speaking to reporters from Dolly’s pen at the Roslin Institute on Friday, the head of the original cloning team, Professor Ian Wilmut, put a brave face on the sheep’s condition.

He said that he was concerned and called for more research into the implications of cloning. But he insisted that the technology was crucial for medical science and denied that he had opened a Pandora’s box by showing that animals could be cloned. “This is an inefficient procedure. We were always aware that there was a risk that we would find things like this. We were very disappointed and very concerned for the animals,” he said.

“We will never know in the case of Dolly whether this condition is because she is cloned or whether it is an unfortunate accident that she developed arthritis. What’s very important is that not only we at the institute, but others who produce cloned animals, should monitor their health throughout their entire life span.”

Dolly seemed alert on Friday as she moved around her pen with the three of her six lambs that keep her company, but occasionally her hind legs appeared a little unsteady. Vets at the institute have put her on anti-inflammatory drugs and prescribed a weight loss and exercise programme. They noticed a few weeks ago that Dolly was showing signs of lameness in her left hind leg.

“Arthritis is not unknown in this age of sheep,” said Dolly’s vet, Tim King. “The strange thing about Dolly is that arthritis normally affects the elbow in sheep. In Dolly, her hip and knee joint are affected.” im Clapp, a vet in the north Pennines with 20 years’ experience of working with sheep, said that he would be astonished to come across a normal sheep with arthritis at so young an age. “In the field, it would be ludicrous to have animals getting arthritis when they were five years old,” he said.

Animal cloning is already known as an unreliable and risky procedure. It took 276 unsuccessful attempts before Dolly was produced. Many cloned animals which are carried to term die shortly after birth and suffer deformities. Some scientists believe the problem is their inability to reproduce the mysterious natural process of “imprinting”, by which, in normal conception, settings that clash on a handful of genes from mother and father are adjusted so that they match.

Even though the few clones which make it to adulthood, such as Dolly, may have seemed healthy, there have already been signs that at the cellular level, they were “pre-aged” from birth. The ewe from whose cell Dolly was cloned was six years old, so some have argued that she is, in a sense, 11.

Prof Wilmut said that the development of arthritis in Dolly was only one minor new doubt to add to the pile. “I don’t regard this as a major setback,” he said. ”Alongside all the other things, the inefficiency and the fact that some of the cloned animals die soon after they are born, it’s just one more small piece.”

Although the idea of human reproductive cloning has caught the public imagination since Dolly was born, Prof Wilmut has been an outspoken opponent of the practice, as have most scientists in the field. Apart from the risks and ethical objections, there are few reasons, apart from notoriety, to conceive, give birth to and rear cloned human beings.

Nick Harris, senior researcher for the anti-abortion group Life, said: “We already knew about Dolly’s abnormal telomeres, which means, crudely, that she is ageing prematurely, so we are not surprised to hear of more defects resulting from the cloning procedure, but this information has a large bearing on those irresponsible scientists who wish to clone humans. “This debate has ceased to be a theoretical exercise. Cloning a human is no longer science fiction, it is science fact.” —Dawn/The Guardian News Service.