Concerns that Dolly, the cloned sheep suffered from early-onset arthritis, were unfounded, a new study suggests.
In fact, the wear and tear on their joints was similar to that of other sheep of their age, regardless of how they were conceived, the researchers say.
Dolly, the first mammal cloned from an adult cell, made innumerable headlines during his life.
It was the subject of close scrutiny, due to the fear that the cloned animals could develop health problems or prematurely age.
Researchers at the University of Nottingham have reexamined their skeleton.
"We felt we needed to establish the direct record – how bad was Dolly?", Said Professor Kevin Sinclair.
"It was very similar to what we saw in our own animals and other sheep naturally conceived & # 39; & # 39;
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took 277 attempts to clone Dolly, and for a time it was without a doubt the most famous sheep in the world.
He made countless headlines over the years, from his birth in July 1996 until his death in February 2003.
His health was monitored closely, including osteoarthritis of his left knee at the age of 5 years.
However, a study last year of the cloned sheep Debbie, Denise, Dianna and Daisy, derived from the cell line that gave rise to Dolly, found evidence of mild or, in one case, moderate osteoarthritis.
The sheep were older than Dolly at age eight, prompting the researchers to re-examine Dolly's case.
Since none of Dolly's X-rays survived, the researchers made an X-ray of her skeleton.
They also made an X-ray of the skeletons of their naturally conceived daughter, Bonnie, and Megan and Morag (the first two cloned animals). of differentiated cells).
These findings were compared with X-rays from healthy and naturally-conceived sheep.
It turns out that the findings in Dolly were not unexpected, given her age.
Sheep rarely live beyond the age of nine or ten years, when they are kept as pets or in the wild.
"We found that the prevalence and distribution of radiographic osteoarthritis was similar to that seen in naturally-conceived sheep and healthy and aged cloned sheep," said Professor Sandra Corr.
"As a result, we conclude that the original concerns that the cloning had caused the early onset of osteoarthritis in Dolly were unfounded. "
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