CaptionDolly the sheep became the world's most controversial animal. Scientific history was written at the Roslin Institute in Scotland, which announced on February 22 that it had produced the first cloned mammal. Biologists took one mammary cell from an adult ewe and inserted it into a sheep's ovum, which divided and developed to become Dolly, carrier of an exact replica of her mother's DNA. The news sparked heated discussions about the ethics of cloning.
