Four clones derived from the same cell line of the original cloned sheep, Dolly, have reached their 9th birthdays in good health.

Dolly’s offspring (Debbie, Denise, Dianna and Daisy) have just celebrated their 9th birthdays and along with nine other clones make up a unique flock of cloned sheep.

The flock is under the care of Professor Kevin Sinclair, an expert in developmental biology, in the School of Biosciences, at the University of Nottingham.

The research, ‘Healthy ageing of cloned sheep’ is the first detailed and comprehensive assessment of age-related non-communicable disease in cloned offspring, according to Sinclair.

Healthy ageing of Somatic-Cell Nuclear Transfer (SCNT) clones has never been properly investigated. There have been no detailed studies of their health.

“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.

“Following our detailed assessments of glucose tolerance, insulin sensitivity, blood pressure and musculoskeletal investigations we found that our clones, considering their age, were at the time of our research healthy,” Sinclair said.

Dolly made history as the first animal to be cloned from an adult cell using the SCNT technique. She was cloned by Sir Ian Wilmut, Keith Campbell and colleagues at the Roslin Institute, part of the University of Edinburgh in Scotland.

Dolly was born on July 5, 1996 and died from a progressive lung disease five months before her seventh birthday.