A chemical biologist who worked at the California Institute of Technology from 1946 until his death, Davidson was prominent in the field he helped create: genomic research. He pioneered the use of physical chemistry and electron microscopy to map genes, and was a founding member of the advisory council to the Human Genome Project.
President Bill Clinton awarded him the National Medal of Science in 1996 for his work. He died February 21 in Pasadena, Calif. He was 85.