Geneticist and Indiana University Distinguished Professor of Zoology. Sonneborn was born in Baltimore, Maryland and received an A.B. from Johns Hopkins University in 1925. Changing direction from an English major, Sonneborn moved into zoology, and in 1928 received his Ph.D. under the direction of renowned philosopher, educator, and geneticist Herbert Spencer Jennings. The next ten years were spent in post doctoral work and as a research assistant at Johns Hopkins, during which time he studied single-celled paramecium and made the crucial discovery of mating types and their control. This discovery along with his other research brought him to the attention of leading geneticists throughout the country and to that of Indiana University's Dean of the Graduate School Fernandus Payne in particular. In 1939 he and his young family made the move to Bloomington, Indiana, and Indiana University where he would remain throughout his career.

During the course of that career, Sonneborn lectured across the country and held temporary positions at many universities, including Princeton, University of Colorado, and University of Chile. He was active in national and international organizations and received various awards and high honors for both his teaching and research, including the Frederic Bachman Lieber Memorial (1967) and the Brown Derby (1971) teaching award; the American Association for the Advancement of Science prize (1946), membership in the National Academy of Sciences, the American Philosophical Society and the Royal Society of London; Honorary D.Sc. degrees from Johns Hopkins (l957) and Indiana (1979) universities; the Kimber Genetics Award (1959); and the Mendel Medal (1965). Professor Sonneborn retired from teaching in 1976 but continued his research and connections with both students and the university up until the time of his death. In 1985 Indiana University initiated the Tracy M. Sonneborn Award to honor a faculty member who has achieved distinction as a teacher and as a scholar or artist. It was designed as a commemoration of Professor Sonneborn, an IU faculty member who clearly distinguished himself in both these areas.