 He then spent three years in the Biochemistry Department at the Stanford University School of Medicine where he was a post-doctoral fellow in Arthur Kornberg's laboratory doing research on DNA-binding proteins.Glassberg moved to Rockefeller University, New York City in 1979 and worked on creating a genetic system using the eukaryote, "Crithidia fasciculata", a trypanosomatid parasite of mosquitos.Glassberg continued his scientific work as one of the founders of ACTAGEN (an acronym for advanced clinical testing and genetics) in March 1982.