Research has proven that cloned animals can live long and healthy lives as the sister clones of Dolly the sheep are aging normally. The Nottingham Dollies, named Debbie, Denise, Dianna and Daisy, recently celebrated their ninth birthday in good health despite their advanced age.

As stated in the journal Nature Communications, the cloned sheeps, born July 2007, do not show any signs of high blood pressure, diabetes or degenerative join diseases. These four are part of a Kevin Sinclair’s flock that also include nine other cloned sheep. Sinclair is a specialist in developmental biology in the School of Biosciences at the University of Nottingham.

These four cloned animals were derived from the mammary gland cell line that led to Dolly’s birth. The other animals were derived from fetal fibroblasts.

However, the researchers admit that some of the animals show signs of mild osteoarthritis. In fact, Debbie has been diagnosed with moderate osteoarthritis. Still, none of the animals require treatment and all are still very mobile.

The findings show the potential of the technique called SCNT (also known as somatic cell nuclear transfer). However, Sinclair asserts that efficiency of SCNT remains low despite the technological advances in recent years. There is still a long way to go before this procedure is perfected.  Still, Sinclair is very optimistic about the future of SCNT.

Moreover, Sinclair points out, “Healthy aging of 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.”

Dolly the sheep was the the first animal to be cloned from an adult cell using SCNT.  Dolly died in February 2003 due to a lung disease.