After winning the Nobel Prize in medicine in 2007, professor Oliver Smithies greeted friends and students at a reception for him on the campus of the University of North Carolina at Chapel Hill. (Karen Tam/AP)

Oliver Smithies, a British-born scientist who won the Nobel Prize in medicine in 2007 for advances that enhanced genetic research to better understand cancer, obesity, heart disease and other ailments, died Jan. 10 in Chapel Hill, N.C. He was 91.

The University of North Carolina at Chapel Hill, where Dr. Smithies had been a professor of pathology and laboratory medicine at the medical school, announced the death. No cause was reported.

Dr. Smithies won the Nobel Prize for developing a technique used to manipulate genes in mice. The university said Dr. Smithies’s lab created the first animal model of cystic fibrosis in 1992.

Dr. Smithies’s work aided in the creation and use of “knockout mice,” which have helped scientists understand how individual genes work. According to a National Institutes of Health genome research webpage, knockout mice are rodents in which researchers have inactivated, or “knocked out,” an existing gene and replaced or disrupted it with an artificial piece of DNA.

Knockout mice have been used to study and model varieties of cancer, among other diseases.

Dr. Smithies shared his 2007 prize with the University of Utah’s Mario Capecchi and Martin Evans of Cardiff University in Britain. On that day, his lab threw together a party for the modest Dr. Smithies. In his cluttered office, little toy mice lined his bookshelves.

“I feel rather peaceful,” Dr. Smithies told the News & Observer of Raleigh at the time. “I’ve been working at the bench for more than 50 years, and it’s nice to find that people appreciate what you’ve done. It feels like what a lot of people have mentioned — a capstone on one’s career.”

Olivier Smithies and his fraternal twin brother, Roger, were born June 23, 1925, in Halifax, England. A bout with rheumatic fever at 7 left him with a heart murmur. The condition was then considered serious enough that he wasn’t allowed to play sports until he was a teenager.

He received a scholarship to the University at Oxford in 1943 and briefly studied medicine before changing his concentration to physiology. He was awarded a bachelor’s degree in physiology in 1946, and a master’s degree and a doctorate in biochemistry from Oxford in 1951.

Dr. Smithies did postdoctoral work at the University of Wisconsin and later worked at the Connaught Medical Research Laboratory at the University of Toronto from 1952 to 1960.

After returning to the University of Wisconsin in 1960, Dr. Smithies was among the first scientists to physically separate a gene from the rest of the DNA of the human genome.

At Chapel Hill, his research continued using gene targeting to create animal models to study human diseases, better understand their cause and progression, and help develop new treatments. His most recent research focused on hypertension and kidney disease.

Last fall, the university launched the Oliver Smithies Research Archive website to make available more than 150 of his notebooks.

Survivors include his wife, Nobuyo Maeda, a nutrition professor at the University of North Carolina.