Memorial services are pending for Sidney Richard Snow, professor emeritus of genetics at the University of California, Davis, who died Tuesday, Feb. 11, in Sutter Davis Hospital from an AIDS-related illness. He was 62 years old. Born and raised in the Los Angeles area, Professor Snow served three years active duty in the U.S. Navy. He received his doctoral degree in botany from UCLA in 1957 and joined the faculty of the UC Davis genetics department that year. His early research focused on the cell genetics and evolution of the plant genera Clarkia and Datura. In 1964 he began studying the genetics of microorganisms, especially yeast. Using radiation-sensitive mutants, he investigated the mechanisms of genetic recombination and the locations and regulation of specific genes. More recently, Professor Snow applied modern genetic engineering techniques to the improvement of wine yeast. The work in his laboratory led to numerous scientific publications, two patents and a chapter in the book "Genetic Improvement of Wine Yeast," an important review of the field. Thousands of students passed through his introductory genetics classes, as well as courses in his specialty area of cytogenetics. Professor Snow was active in the early development of television as a teaching tool for reaching large numbers of students in multiple classrooms and for producing tapes for review sessions. He took advantage of newly emerging techniques to continuously update laboratory exercises for his courses. His university contributions included serving as acting chair of the genetics department from 1965 to 1967 and as chair of the department from 1979 to 1984. He also was associate dean of biological sciences in the College of Letters and Science from 1970 to 1975. Professor Snow was a talented amateur photographer, who used large format cameras in both black-and-white and color media. He also enjoyed restoring early cameras and microscopes to museum quality, and his home laboratory-darkroom was fully equipped for photography, microscopy and the growing of orchids from seeds. An avid orchid hobbyist, he designed and built two greenhouses and a lath house and was widely recognized for his extensive collection of orchid species. As a service to orchid propagators, he developed a new technique for orchid seed germination, and had marketed a laminar-flow cabinet kit of his own design for use in orchid propagation and other sterile procedures. He also was particularly interested in the music of Bach and other early composers, which he played on the harpsichord. He was in the midst of building an elaborate double-keyboard harpsichord. Professor Snow also wrote specialized computer programs in order to keep track of his large collection of orchid species and the results of genetic crosses he made from yeast, orchids and California's Delphinium species. He was a member of the Genetics Society of America, Botanical Society of America, California Botanical Society, American Association for the Advancement of Science, Sacramento Orchid Society and Orchid Society of America. He served as an associate editor of the Yeast Newsletter, published by the International Union of Microbiological Societies. He is survived by his longtime companion, Warren Roberts, of Davis and by his brother, Donald Snow, who is a professor of mathematics at Brigham Young University in Provo, Utah. He also leaves special friends Tom Flynn, Ralph Kunkee, Norma Lang, and Dennis Stewart, all of Davis; Ernest Brown of Sacramento; John DiDonna of San Francisco and Lorene Embry of Moreno Valley. In lieu of flowers, family and friends request that any memorial contributions be made to the Sacramento AIDS Foundation.