Capecchi, Mario Renato (1937-…), an Italian-born American biologist, won the 2007 Nobel Prize in physiology or medicine for his contribution to a technique used to modify genes in mice. Genes direct the formation, growth, and reproduction of living cells and organisms. Capecchi shared the prize with fellow American biologist Oliver Smithies and the British geneticist Sir Martin John Evans. The three scientists developed methods used to produce knockout mice, strains of laboratory mice in which a particular gene has been inactivated or “knocked out.” Scientists use knockout mice as models for studying gene function and disease.
In the 1980’s, working independently, Capecchi and Smithies studied a process called homologous recombination. Homologous recombination occurs between or within chromosomes, the structures in cells that carry genes. These genes are encoded in the structure of a chainlike molecule called DNA (deoxyribonucleic acid). Homologous recombination occurs when similar chromosomes exchange homologous (corresponding) stretches of DNA, including any genes encoded within them.
Capecchi demonstrated that homologous recombination can also occur between a cell’s chromosomes and artificially injected DNA. This fact enables scientists to transfer new DNA onto a chromosome, altering or inactivating specific genes. This artificial use of homologous recombination has become known as gene targeting. Capecchi showed that it could be used to replace genes in the cells of higher animals. Smithies reached a similar conclusion.
Capecchi and Smithies’s work enabled scientists to knock out genes within individual mammalian cells. Around the same time, Evans developed the additional methods necessary to produce entire knockout mice. Scientists could then observe the effect of the targeted gene by comparing the development of the knockout mice with that of mice with the active gene. Scientists have since used knockout mice to study the role of various genes in development and human diseases such as cystic fibrosis, diabetes, and hypertension.
Capecchi was born in Verona, Italy, on Oct. 6, 1937. In 1941, during World War II (1939-1945), his mother was sent to a concentration camp. She left him in the care of another family, but that living situation ended about one year later. He then spent time in hospitals, orphanages, and with his father, but he was often homeless. In 1946, he reunited with his mother, an American citizen, and they moved to the United States. Capecchi studied chemistry and physics at Antioch College in Yellow Springs, Ohio, graduating in 1961. He received his Ph.D. degree in biophysics at Harvard University in 1967. Following a fellowship at Harvard from 1967 to 1969, he joined the faculty in biochemistry at Harvard Medical School, where he remained until 1973. Since then, he has been professor of human genetics and biology at the University of Utah, in Salt Lake City.
See also Evans, Sir Martin John ; Smithies, Oliver .
