In 1997 photographs of a sheep called Dolly appeared on the front page of newspapers around the world . she looked quite ordinary but Dolly was different from other sheep . she was an identical copy of another adult sheep . In other words she was a clone . Before Dolly scientists had only been able to clone large animals using cells taken from embryos . they had tried to do it using cells from adult animals but I hadn't worked until now . That's why Dolly was so special