The University of Nottingham says that Keith Campbell, a prominent biologist who worked on cloning Dolly the sheep, has died at 58.
University spokesman Tim Utton said Thursday that Campbell, who had worked on animal improvement and cloning since 1999, died last Friday. Utton did not specify the cause of death. Campbell had worked at the university until recently.
Campbell began researching animal cloning at the Roslin Institute near Edinburgh in 1991. The experiments led to the birth in 1997 of Dolly the sheep, the first mammal to be cloned from an adult cell.
The sheep's creation became a scientific sensation and sparked debates about the ethics of cloning. Dolly died in 2003.