When was the first mammal successfully cloned?

The story behind the answer

1996 is correct because that’s when Dolly the sheep—the first mammal cloned from an adult somatic cell—was born at the Roslin Institute in Scotland. Scientists used somatic cell nuclear transfer: they took the nucleus from an adult udder cell and inserted it into an enucleated egg, then stimulated it to develop into an embryo. Dolly’s creation was announced in 1997, which sometimes causes confusion, but she was born in July 1996.

Dolly proved that specialized adult cells could be reprogrammed to develop into an entire organism, overturning assumptions about cell differentiation and paving the way for stem cell research. Memory tip: “Dolly in ’96”—think Dolly Parton and the 1990s—links the famous name to the year.