Dolly the sheep

Who would have thought that a Scottish sheep named Dolly could cause an international uproar? But she has, and it's all because of her unorthodox beginnings. Dolly is not an ordinary sheep, produced through the mating of a ewe and a ram. She is a clone, an exact genetic replica of her donor "mother," a six-year-old female sheep. And that fact, together with another recent announcement that scientists in Oregon have cloned monkeys from embryonic …

…tiny ball of cells called a blastocyst, the researchers placed it into the uterus of an adult female sheep -- Dolly's surrogate mother. The sheep carried Dolly through a normal pregnancy and gave birth to the lamb that has caused so much controversy. When Wilmut and his collaborators analyzed the DNA of Dolly's cells, they found that it was identical to the DNA of the donor udder cell. That is why Dolly is a clone.