Dolly the sheep did not have early-onset arthritis

23 November 2017
Posted by Chris Smith.

Dolly the cloned sheep didn't have early-onset arthritis, a new study looking at her skeleton has concluded.

Born into a blaze of publicity as the world's first cloned animal in 1996, Dolly the sheep was a scientific superstar. Nearly as famous as her namesake, the country and western singer Dolly Parton, she was created by transferring the DNA from an udder cell taken from a ewe into the egg cell of another sheep from which the DNA had previously been removed. The resulting embryo was then implanted into a surrogate sheep's uterus and a successful pregnancy ensued.

The process broke new ground in biotechnology and created huge enthusiasm and controversy in equal measure as people began to realise the opportunities and the implications of what being able to make a genetic copy of yourself might mean. An endless supply of donor spare parts, for instance.

But when, aged 5 and a half years old, Dolly later developed a limp and vets diagnosed left knee arthritis as the cause, scientists were concerned over what this might mean. Was Dolly ageing faster than she should, perhaps because the DNA used to create her came from an adult cell to start with?

Now, just shy of 15 years after Dolly died in February 2003, scientists at the University of Nottingham have revisited the question. Although all of Dolly's original records and investigations have long since been lost, her skeleton is preserved in the collection of National Museums Scotland, in Edinburgh. So Sandra Corr and her colleagues have carried out a detailed radiological - X-ray - investigation of the remains of Dolly, as well as her daughter Bonnie (who was born naturally), and two other cloned sheep, Megan and Morag.

Writing in Scientific Reports, the clones show no greater evidence of osteoarthritis than naturally-conceived animals, the team conclude, although they acknowledge the limitations of a study based only on bones and without the soft-tissues to consider. 

"Concerns raised over a direct link between Dolly's osteoarthritis and cloning were therefore unfounded," they say...

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