Over the past decade, researchers around the world have cloned a number of mammals, including mice, cows, goats and pigs. But dogs’ reproductive physiology is just too idiosyncratic for easy manipulation. So when a team of South Korean scientists announced this week that it had cloned an Afghan puppy, the feat evoked admiration from other researchers.

A team of about 15 people worked for nearly three yea-rs to extract eggs and impla-nt more than 1,000 cloned canine embryos in surrogate mother dogs. They got only three pregnancies, and only one dog that survived into healthy puppyhood. Although the work demonstrated that dogs could indeed be cloned, that’s a poor success rate. Some dog lov-ers may be salivating for the chance to clone a favoured pet, but that prospect seems far off given the arduous nature of the task.

The Korean team hopes that cloned dogs may someday be used to study the progression of diseases that are similar in dogs and humans. But the larger lesson here is that the Koreans are truly a force to be reckoned with. This team was the first to clone human embryos and extract stem cells from them, and now it is the first to clone a dog, perhaps the most difficult feat in mammalian cloning. The centre of gravity in cloning and stem cell research may be shifting away from America. — The New York Times