Dolly was a sheep who was the first animal to be artificially cloned from cells taken from another adult animal. She was born in July 1996 and was put to death in February 2003, suffering from a progressive lung disease. She had lived about half the normal life expectancy of her breed. It is unclear whether Dolly’s early death was related to the fact that she was a clone.
The British scientist Ian Wilmut, head of a team of researchers in Edinburgh, Scotland, announced Dolly’s existence in February 1997. Until then, scientists had not succeeded in making a clone of any adult mammal. A clone is a genetically identical copy of another organism. Cloning can occur naturally. Identical twins are clones, and some simple animals reproduce by producing clones.
Some observers believed this achievement was a great scientific advance. They foresaw agricultural improvements to livestock and new medical applications, including new drugs for human diseases, treatments for genetic disorders, and the possibility of transplanting modified organs from animals to humans. Other people expressed serious concern that the new technique opened up the possibility of cloning human beings.
See also Cloning ; Genetic engineering ; Wilmut, Ian .
