Cloning won’t get you the exact pet you’ve lost, because every dog or cat is the product not only of genetics, but also of many random genetic events during development. For example, a clone of a spotted cat won’t have spots in the same places as the original because of random timing of cell divisions carrying different color hairs. A clone will also differ because of environmental factors such as experiences and nutrition.

Cloning presents a problem in the world of breeding and competition. No dog or cat registry will register cloned animals at this time. Most breeders feel that cloning runs contrary to the objectives of improving a breed because it simply produces genetic replicas of existing animals. Even if such dogs or cats are outstanding breed representatives, making more of them risks reducing a breed’s gene pool. So perhaps it's no surprise that the first dog owner to spend $150,000 for a clone has not earmarked that money for a Westminster Best in Show winner with a fancy name, but for a beloved and much-missed pet pit bull who simply goes by Booger.

Why Dogs Are So Hard to Clone: To clone a mammal, scientists start with harvested mature eggs. But because dogs only ovulate twice a year, and scientists haven’t found a way to induce canine ovulation, eggs can be hard to come by. And unlike other mammals, in which eggs mature in the ovaries, dog eggs mature in the oviducts about 72 hours after ovulation. So instead of aspirating eggs fairly easily from the ovaries, they must be surgically removed from the tiny oviduct. 

After removal, the eggs’ genetic material is replaced with that of the animal to be cloned. The resulting embryos are grown in the laboratory for several days and then implanted into surrogate mothers that have been given hormones to prepare them for pregnancy. But nobody has ever been able to grow dog embryos outside of a dog. 

So as soon as the eggs begin to develop into embryos—within four hours of starting the cloning process—they must be surgically placed back into the oviduct. And because no hormones have ever been found that prepare dogs for pregnancy, the eggs must be implanted back into the same dog from which they were just removed.

Would you clone your pet? Is it worth the cost?  Discuss with other pet owners on our message boards!