How did the work of th morgan and company contribute to the eventual discovery that dna was the genetic material in the cell?

Thomas Hunt Morgan received a Nobel Prize in Medicine in 1933 for his theory on the chromosomal theory of inheritance. Using Drosophila melanogaster (fruit flies), he and his students were able to perform ground-breaking genetic research. They narrowed the search for genetic materials to either DNA or proteins and eventually proved that the genes are actually located in chromosomes.  

Where are they though?