When was the first successful cloning of a mammal completed?

Dolly the sheep was born in 1996 at the Roslin Institute in Scotland, making her the first mammal cloned from an adult somatic cell. Her creation showed that specialized adult cells could be reprogrammed to produce an entire animal. Dolly became one of the most important scientific milestones in mammalian genetics and developmental biology. Her birth also sparked major ethical and medical debates.