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Scientists in South Korea announced this week that they have cloned a dog. It's an Afghan hound named Snuppy, as in Seoul National University puppy. Several species have been cloned in the past. But as VOA's Barbara Klein reports, duplicating a dog was a much more difficult feat.
Scientists in South Korea announced this week that they have cloned a dog. It's an Afghan hound named Snuppy, as in Seoul National University puppy. Several species have been cloned in the past. But as VOA's Barbara Klein reports, duplicating a dog was a much more difficult feat.
KLEIN: Snuppy comes from skin cells of an Afghan hound. The scientists took the DNA from the nucleus of those skin cells and put it into an egg, and used chemicals to jump-start cell division. The egg, now an embryo, was then implanted in the uterus of a Labrador Retriever. Cloning is always a complicated process, but in dogs, it is especially so. Dr. George Seidel is professor of Reproductive Physiology and Endocrinology at Colorado State University. He has cloned cattle, but says dogs are far more difficult to clone because they don't have regular reproductive cycles.
SEIBEL: Dogs have a reproductive cycle, and then they go into a period of anestrus for about half the year and then they have another one and nobody is entirely sure how this regulated. In most other species we work with, either they have very regular reproductive cycles that are on the short side or they're longer, but we can manipulate them so we can start a cycle almost at will. And it's quite important that the embryo and the reproductive tract it goes into be at the same stage. In other words, one needs to synchronize those things. In the dog, that is very difficult. Information from other species accumulated so that these things could be done successfully in the dogs and even with that accumulated information, it was still a heroic task to accomplish this.
KLEIN: We've been told scientists pursue cloning because, in the end, they're looking for research that tells them something about stem cells and how we can ultimately cure some diseases that hurt humans. How does the dog fit in to this process of developing cloning for the purposes of stem cell research?
SEIBEL: You are correct that one of the ultimate applications of cloning is in fact regenerative medicine. Things like producing a pancreas for people with diabetes, or a liver for people with cirrhosis, or even neurons for people with spinal cord injuries. Those applications will come along. The dog does frankly not contribute a lot new to that, other than demonstrating that yes, even in difficult situations, with persistence, you can make the system work.
KLEIN: Scientists have already cloned sheep, mice, rats, cats, cattle ? you yourself have done cows ? rabbits, a horse and a mule. Have we learned anything from those clonings already?
SEIBEL: Yes, these experiments are providing certain kinds of fundamental information on cancer, on aging, on birth defects, loss of pregnancies. Now, having said all that, these experiments, like good experiments, have raised more questions than answers, but we weren't even smart enough to know we had a problem in some cases. To know even what the questions were. So biology has advanced tremendously because of these things.
KLEIN: How are the cattle that you've cloned doing?
SEIBEL: There are problems with a lot of the pregnancies of cloned cattle. The abortion rates are higher than normal, by a lot. When the calves are born, they are not quite right. Now it turns out that the problems we see with clones, one sees in everyday reproduction as well, but just in a lower incidence. And so they actually provide models to study certain kinds of problems, and in fact these problems occur in human pregnancies as well. And while we might say it's one or two percent, that ends up being an awful lot of babies in the world. So in that sense these abnormalities are, in fact, giving us insights to those problems.