Dolly the sheep, the first mammal cloned from an adult, was euthanized after being diagnosed with a progressive lung disease, her creators said Friday. She was born in 1996 and revealed to the world in 1997; scientists studied her as she began to exhibit symptoms of aging as though she were much older than she was, and she began to exhibit signs of arthritis before her sixth birthday. She was six and a half years old when she died, and is survived by her five children.
More information can be found at the Washington Post.