LONDON (AP) -- Keith Campbell, a prominent biologist who worked on cloning Dolly the sheep, has died at 58, the University of Nottingham said Thursday.
Campbell, who had worked on animal improvement and cloning since 1999, died Oct. 5, university spokesman Tim Utton said. He did not specify the cause, only saying that Campbell had worked at the university until his death.
Campbell began researching animal cloning at the Roslin Institute near Edinburgh in 1991. The experiments led to the birth in 1996 of Dolly the sheep, the first mammal to be cloned from an adult cell.
The sheep was named after voluptuous singer Dolly Parton. Researchers at the time said that the sheep was created from a mammary gland cell, and that the Parton offered an excellent example.
The creation of the sheep captured the public imagination and instantly became a scientific sensation. The experiments drew admiration but also anger from some who raised questions about the ethics of cloning.
Animal rights activists were outraged, while the Church of England expressed reservations. Dolly was put down in 2003 after she developed lung disease.
Campbell later joined Nottingham University as professor of animal development, where he continued research into the cloning process. He was particularly interested in assisted reproduction in both animals and humans, and studied ways to develop reproductive technologies in farm animals to enhance breeding and maintain food security.
He believed research into medical use of embryonic stem cells would eventually lead to important breakthroughs despite opposition from some who found the technique abhorrent.
"There are groups that believe that life begins at conception and that you should not do any research involving embryos at all," he said in a 2001 interview. "But we have also been able to inform people of the potential benefits, and once they learn about it they are much more likely to be in favor of it."
He said stem cells from embryos have the unique ability to be developed into many different types of human cells, including blood, muscle and nerve cells.
"Broadly, I would say they may be a major breakthrough in human medicine that will improve the quality of life for a large number of the population, particularly those with age-related disorders," Campbell said.
The scientist was awarded the Shaw prize for medicine and life sciences in 2008, along with Ian Wilmut, the lead scientist in the team that created Dolly, and Nobel-winning scientist Shinya Yamanaka.