How They Cloned a Sheep
4. The egg cell divided until it developed into an embryo. An embryo is the early stage of an animal before it has been born or hatched. This embryo was placed inside a third sheep. Five months later, this sheep gave birth to Dolly.
Photos: Dr. Ian Wilmut and Dolly; Dolly and her birth mother, courtesy of the Roslin Institute; Illustrations: Clay Meyer