Since the very beginning, it has been one of the most pressing questions in the science of cloning; do the resulting copies of individuals suffer from advanced aging? This concept originally became a concern when the very first mammal to have been cloned from an adult cell, Dolly the sheep, died at the relatively young age of six and a half years old from an illness that is usually associated with old age, osteoarthritis.
There is now, however, a new study which has shown that this does not necessarily have to be the case. By re-cloning the same sheep that gave rise to Dolly and tracking how the clones have aged over the last eight years, scientists found that while some individuals did develop mild to moderate osteoarthritis, it showed that their overall health was remarkably good.
Dolly first made history in 1996 when she became the first mammal in the world to become cloned from an adult cell using a technique known as Somatic-Cell Nuclear Transfer or SCNT. The SCNT technique involves removing the nucleus from a cell which is taken from an adult sheep, placing the nucleus into an empty embryo that is taken from a second sheep, and then placing the combination of the nucleus and embryo into a third sheep, who is acts as a surrogate mother. The resulting lamb, Dolly, was a clone of the first sheep.
To recreate the study, scientists took the same cells that produced Dolly and then cloned them to create four new clones, which they named Debbie, Denise, Dianna and Daisy. In addition to the four “sibling” clones, the scientists also produced nine other clones using different donors. Over the last seven to nine years, the researchers have conducted a detailed analysis of the animals’ health, assessing a vast range of factors. After detailed assessments of glucose tolerance, insulin sensitivity, blood pressure and musculoskeletal investigations, the researchers found that the clones were considered, at the time of the study, health.
However, there is still a long way to go before the SCNT technique is perfected, but this study definitely helps to provide evidence that this method does not mean the clones will be born at the same age as the cells that they were derived. This study has the potential to create a crucial impact on the use of SCNT to produce stem cells from adults or other cloned animals.