Several decades ago the idea of cloning animals became a reality after “Dolly” the sheep became the first of such to have been created inside of a laboratory and born into our world.
New research on the bones of Dolly the sheep show that she did not develop arthritis, or age prematurely, as many experts had predicted would occur.
Scientists have also found in their research information in which suggests cloning is far safer than previously thought, with little to no adverse health effects compared to that of a normal sheep.
The world’s first animal cloned from an adult cell was born in Edinburgh, Scotland, the United Kingdom back in 1996 and died in 2003 at the age of six.
At the time scientists believed that multiple genetic problems would be caused by the cloning process and had led Dolly to age rapidly, leading her to develop painful osteoarthritis.
Contrary to those beliefs, however, a new radiographic assessment of her skeleton by experts the universities of Nottingham and Glasgow found that she had no more signs of aging than any other sheep of a similar age.
The team also examined her offspring, Bonnie, as well as two other cloned sheep, Megan, and Morag, and found none of them showed any signs of unusual arthritis reaffirming the belief that there is little danger.
Sandra Corr, Professor of small animal orthopedic surgery at Glasgow University, said, “We found that the prevalence and distribution of radiographic osteoarthritis were similar to that observed in naturally conceived sheep, and our healthy aged cloned sheep.”
She went on, “As a result, we conclude that the original concerns that cloning had caused early-onset osteoarthritis in Dolly were unfounded.”
Dolly was created using a then relatively new technique called somatic cell nuclear transfer, whereby the nucleus from the cell of an adult sheep is transferred to an unfertilized egg before being implanted into a surrogate ewe for birth. It meant that Dolly had exactly the same DNA as the donor sheep.
Initially, she seemed healthy and was successfully mated to produce six lambs naturally. However, in late 2001 she began to walk stiffly.
The following year, Prof Ian Wilmut, who led the team which cloned Dolly at the Roslin Institute at Edinburgh University, announced that she had gone lame and was suffering from arthritis in her left hind leg, hip, and knee.
As heartbreaking as it was to researchers, she was euthanized in February of 2003.
At the time, Prof Wilmut said there was no way of knowing if the problems were down to cloning or were just a coincidence that Dolly had experienced, but the scientific community became concerned, and shares in the PPL Therapeutics who largely funded the project, immediately slumped.
However, the Nottingham team decided to take a closer look at the skeleton to find out for themselves whether Dolly really was suffering from premature arthritis. The traveled to the National Museum of Scotland in Edinburgh, where Dolly is kept, to scan her bones.
The team found no evidence of any abnormal bone conditions that would not normally be expected of a sheep of the same age.
Last year, the exact same team was able to prove that clones produced from Dolly’s cell-line, nicknamed the Nottingham Dollies, also had not aged prematurely.
“Our findings of last year appeared to be at odds with original concerns surrounding the nature and extent of osteoarthritis in Dolly, who was perceived to have aged prematurely,” added Professor Kevin Sinclair of Nottingham University.
Sinclair continued, “Yet no formal, comprehensive assessment of osteoarthritis in Dolly was ever undertaken. We, therefore, felt it necessary to set the record straight.”
“She did become lame at around 5½ years and an x-ray of her left knee at the time revealed evidence of osteoarthritis and that was about as far as it went,” said Professor Sinclair.
Professor Sinclair determined in his conclusion that there were no signs that Dolly had aged prematurely.
The majority of the data compiled and published in<a href="https://www.sciencenews.org/article/dolly-sheep-bones-normal-arthritis">Science News</a>, suggests that cloning thus far is relatively safe and useful for progress in both scientific research and the medical field.
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