Hershey-Chase experiment

In 1952, [Alfred Hershey]? and [Marsha Chase]? conducted a series of experiments that identified DNA to be the genetic material of phages and, ultimately, of all organisms.

A phage is a small virus that infects bacteria. Like a virus, it consists of a protein hull that encloses the genetic material. Hershey and Chase used [T2 phage]?s. When a phage infects a bacterium, it inserts its genetic material into the bacterium, while its hull remains outside.

In a first experiment, T2 phages with radioactive ³²P-labeled DNA infected bacteria. In a second experiment, T2 phages with radioactive ³⁵S-labeled protein infected bacteria. In both experiments, bacteria and phage leftovers were then separated by centrifugation?.

In the first experiment, most of the used radioactive molecules were found in the infected bacteria, while in the second experiment most radioactivity was found in the phage leftovers. That shows the DNA to be the genetic material and protein to be the hull material of phages.