Researchers from the University of Nottingham have now shown that cloned animals are just as healthy as non-clones. A group of cloned sheep, ages 7 to 9, were tested and found to be in good health, despite previous fears that cloning could cause animals to age quickly. The details are in a study just published in the journal Nature Communications.
A little over 20 years ago, the first animal was cloned using a technique called somatic-cell nuclear transfer, or SCNT. The domestic sheep, Dolly, had been cloned from an adult mammary gland cell. This led to concerns that she might age rapidly and develop age-related diseases early. She was diagnosed with osteoarthritis later in life but whether or not it was caused by cloning was unknown. Dolly has since passed away but no research had been done on long-term clone health.
The research team tested a group of thirteen cloned sheep. Four of the sheep are clones of Dolly; the others are clones of a sheep named Lleyn. All of the sheep are between the ages of seven and nine now and are considered seniors. The team measured blood pressure and insulin response. They also performed both musculoskeletal and metabolic assessments. The researchers then conducted radiological exams on all of the sheep to look for signs of osteoarthritis, since that was always a concern with Dolly.
The researchers found no serious health problems in the cloned sheep. A few showed early signs of osteoarthritis but that was expected based on their ages. The clones were compared to normal, healthy sheep and there were no significant differences.
These findings suggest that there are no long-term health effects for cloned animals derived from SCNT. Cloned animals have normal lifespans and are just as healthy as non-clones. This type of research is important for understanding and perfecting cloning techniques such as SCNT.
D. Sinclair et al. Healthy ageing of cloned sheep. Nature Communications (2016).