In the early twentieth century biologists thought that proteins carried genetic information. This was based on the belief that proteins were more complex than DNA. In 1928 Frederick Griffith's research suggested that bacteria are capable of transferring genetic information through a process known as transformation. Research by Avery, MacLeod, and McCarty communicated in 1944 isolated DNA as the material that communicated this genetic information.
The Hershey–Chase experiment, often called the "Waring Blender experiment," was conducted in 1952 by American bacteriologist and geneticist Alfred D. Hershey and his research partner American geneticist Martha Chase at Cold Spring Harbor Laboratory, New York. The experiment showed that when bacteriophages, which are composed of DNA and protein, infect bacteria, their DNA enters the host bacterial cell, but most of their protein does not, confirming that DNA is the hereditary material.
Hershey & Chase, "Independent Functions of Viral Protein and Nucleic Acid in Growth of Bacteriophage," J. Gen. Physiol. 36 (1952) 39-56.
Judson, The Eighth Day of Creation, 108. J. Norman (ed) Morton's Medical Bibliography 5th edition (1991) no. 256.