Dolly, the cloned Finn Dorset lamb born in Scotland in 1997, is surely the most famous sheep on the planet since she was the first clone to be followed by the popular press. Frogs and mice had been cloned years before, and those feats were of great interest to the scientific community, but invisible to the general public. Dolly (who died in 2003) was a large, fluffy, familiar animal. She was cloned by ian Wilmut and his colleagues at an agricultural research facility in Scotland, using a process known as “nuclear transplantation”—the entire nucleus of the donor cell, the packaged DNA, and all its paraphernalia were transplanted into a sheep’s egg whose own nucleus had been removed. Thus, dolly is the genetic replica, or clone, of the animal who provided the nucleus, not the animal who provided the egg. The donated nucleus came from a mammary cell, which prompted the lamb’s creators to name her after the country western singer with the hitherto most famous mammary glands.

Long before there was a real clone, however, there were dozens of fictional clones cranked out in dozens of novels: some eloquent, some exciting, some scientifically plausible, some none of the above. Perhaps the most famous are the dinosaurs of Michael Crichton’s 1990 novel Jurassic Park. Resurrected from scraps of dinosaur DNA rescued from the stomachs of mosquitoes that had been trapped and preserved in amber just after feasting on dinosaur blood some 100 million years ago, these unpredictable creatures clomped their way  …