Dolly The Sheep: Cloning Isn’t Linked To Early Ageing, New Study Says

It was back in 1996 when Dolly the Sheep made it to the headlines for being the first successfully cloned mammal in history. She was cloned from an adult cell using the somatic-cell nuclear transfer (SCNT) technique. In the process, the DNA of a sheep egg was removed and replaced with DNA from a frozen udder cell of a sheep. The fused egg was then made to grow into a fertilized embryo and then transferred into surrogate sheep. The process involved no sperm.

But, after suffering from osteoarthritis and an incurable lung infection, Dolly the sheep died prematurely at the age of six in 2003. Dolly's death raised concerns that cloned animals might age faster as compared to normal offspring.

However, a new study from the University of Nottingham has proved that the cloning process doesn't affect the physical well-being of the animals, reported The Guardian.

The research team, led by Prof Kevin Sinclair, has found that Debbie, Denise, Dianna and Daisy, who were all cloned using cells from the same adult sheep as Dolly in July 2007, are living healthy lives at age nine, indicating that cloned animals age normally. The team examined a total of 13 cloned sheep including nine, which were cloned from foetal skin cells between 2006 and 2008.

The researchers performed a number of tests, including bones, joints and muscles assessment tests, along with blood pressure measurements. The sheep showed no signs of metabolic disease and all having normal blood pressure.

"One of the concerns in the early days was that cloned offspring were ageing prematurely and Dolly was diagnosed with osteoarthritis at the age of around five, so clearly this was a relevant area to investigate," said Professor Kevin Sinclair, reported Mirror.

He added that following the research team's detailed assessments of glucose tolerance, insulin sensitivity, blood pressure and musculoskeletal investigations, it has been found that the clones, considering their age, are completely in good health.

The research findings have been published in the journal Nature Communications.