Dolly was a female sheep—and the first mammal ever cloned from an adult cell. Her preserved remains are on display at the National Museum of Scotland in Edinburgh. Mike McBey via Wikimedia Commons ...

He showed that specialized cells retain the genes to form an organism.

After studying zoology at Oxford, his discovery that all body cells have the same genes led to the cloning of Dolly the Sheep in 1996. Working as a young researcher in 1962, he took the genetic ...