 His mentor was future Nobel Prize winner Max Delbrück.After post-doctoral training with Gunther Stent at the University of California, Berkeley and Theodore Puck in Genetics at the University of Colorado at Denver and Health Sciences Center, he was a professor of Biochemistry at Brandeis University, Boston, Massachusetts, from 1958-1969.He joined the Department of Biology at the University of California, San Diego where he was a professor from 1970 through 1983.