LONDON, Jan 4: The creator of Dolly the Sheep warned on Friday against plans to clone humans after he disclosed that the animal had contracted premature arthritis, which raised questions about the safety of mammal cloning.

“I think there was already plenty of evidence that it would be completely irresponsible to think of producing a person,” said Professor Ian Wilmut, who led the team which cloned Dolly in 1996.

Experience with animals has already shown that most clone pregnancies fail, or result in offspring that were stillborn or deformed.

“I think in a wider context we have to be cautious about the way in which we think of using this technology,” Wilmut told the press.

“The fact that Dolly has arthritis at this comparatively young age suggests that there may be problems. We do not know and it’s very important that we look,” he said.

There was no way of knowing if the five-year-old’s condition was a result of the cloning process, he added.

He said: “Dolly has arthritis in her left hind leg at the hip and the knee.

“We can’t tell how it will develop but she is responding well to treatment with anti-inflammatory drugs.”

Dolly, the first mammal to be cloned from an adult cell, was being closely monitored by veterinary staff at the centre, Wilmut said.

“In every other way she is perfectly healthy and she has given birth to six healthy lambs,” said Wilmut.

Sheep have a life expectancy of 13 years.

In May 1999, research suggested Dolly might be susceptible to premature aging.

A PPL team, reporting in the journal Nature, examined age-linked structures in Dolly’s cells called telomeres. The structures were slightly shorter than would be expected in a sheep of her age which had been born normally.

The anti-abortion and pro-life charity Life, called for an immediate halt to all cloning research involving human cells.

Nick Harris, Life’s senior researcher, said: “We already knew about Dolly’s abnormal telomeres, which means crudely that she is aging 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. We must put a stop to all cloning programmes involving human tissue.”—AFP