Cloning has been under the spotlight for the past 20 years since the birth of Dolly the sheep, and now Dolly’s clones, known as the ‘Nottingham Dollies’, have become the focus of research.
Health checks on Debbie, Denise, Dianna and Daisy, the nine year old the Finn-Dorset clones, which are genomic copies of Dolly, have shown the sheep are still healthy.
Professor Kevin Sinclair led a team at the University of Nottingham through several veterinary checks including radiological examinations of joints, MRIs and metabolic and cardiovascular testing.
After Dolly developed osteoarthritis at a relatively young age of five, questions were raised as to the effects of cloning on premature aging. The study showed none of the sheep, which were eight years old at the time of the testing, were lame and most only had mild osteoarthritis, apart from Debbie who had moderate osteoarthritis.
Along with no signs of clinical degenerative joint disease the metabolic output, blood pressure and kidney output were all within normal ranges for average sheep of similar age. The results indicate these cloned sheep are living long and relatively healthy lives, with no indication of premature aging.
Professor David Gardner a developmental physiologist said “If cloning was accelerating aging, we would have seen it in this group of sheep.”
Prof Sinclair, who worked on Dolly’s original team said: “there could be a realistic prospect of using somatic-cell nuclear transfer to generate stem cells for therapeutic purposes in humans, as well as generating transgenic animals that are healthy, fertile and productive.”
Ethics have always been a big issue when cloning is the topic; some people believe it may lead to designer animals and possibly humans.
The high level of miscarriage in cloned animals is another area of ethical concern.
Prof Sinclair explained that about three per cent of embryos which were transferred resulted in live births with Dolly, whereas more recent figures suggests a 20 per cent transfer.
Therefore, although there are more complications with cloning than natural births, this increase in embryo transfer seems to indicate the efficiency has improved over the years, which may provide positive steps forward in developing therapies for human use.