Cloned Sheep Appear to Age Normally

New York Times (July 26, 2016): Dolly the Sheep's Fellow Clones, Enjoying Their Golden Years, by Joanna Klein: 

Dolly, the first cloned sheep, born in 1996, appeared to be older than her years and was put down at just age six after being diagnosed with osteoarthritis and tumors in her lungs.  Other cloned mammals have developed diabetes or been plagued with obesity.  Several jurisdictions have reacted to these development by passing restrictive legislation:

Not only did many countries, including Canada and Australia, ban reproductive cloning in animals, but the United Nations banned all kinds of cloning in humans in 2005.  Last year the European Union made importing food from cloned animals or their offspring illegal.

But four other sheep created from the same cell as Dolly was are now old and, in contrast to Dolly, are enjoying healthy lives.  About sixty in human years, they show a normal incidence of heart disease, type two diabetes, and osteoarthritis.  Their longevity appears to answer the lingering question whether cloned animals age prematurely.  The data are reflected in studies of cloned cattle and mice.  One conclusion that might be drawn is that "once cloned animals survive the first few years of life, they won’t die any sooner than other animals."

Scientists think that safe and efficient cloning procedures will emerge in five to ten years.  One hope is that improved cloning techniques will help us grow food for the ever-growing human population, protect endangered species, and perfect new medical therapies.