Editing Molecular biology (section)

== Hershey–Chase experiment ==
{{Main|Hershey–Chase experiment}}
[[File:Hershey Chase experiment.png|thumb|Hershey–Chase experiment]]
Confirmation that DNA is the genetic material which is cause of infection came from the [[Hershey–Chase experiment]]. They used ''E.coli'' and bacteriophage for the experiment. This experiment is also known as blender experiment, as kitchen blender was used as a major piece of apparatus. [[Alfred Hershey]] and [[Martha Chase]] demonstrated that the DNA injected by a phage particle into a bacterium contains all information required to synthesize progeny phage particles. They used radioactivity to tag the bacteriophage's protein coat with radioactive sulphur and DNA with radioactive phosphorus, into two different test tubes respectively. After mixing bacteriophage and ''E.coli'' into the test tube, the incubation period starts in which phage transforms the genetic material in the ''E.coli'' cells. Then the mixture is blended or agitated, which separates the phage from ''E.coli'' cells. The whole mixture is centrifuged and the pellet which contains ''E.coli'' cells was checked and the supernatant was discarded. The ''E.coli'' cells showed radioactive phosphorus, which indicated that the transformed material was DNA not the protein coat.

The transformed DNA gets attached to the DNA of ''E.coli'' and radioactivity is only seen onto the bacteriophage's DNA. This mutated DNA can be passed to the next generation and the theory of Transduction came into existence. Transduction is a process in which the bacterial DNA carry the fragment of bacteriophages and pass it on the next generation. This is also a type of horizontal gene transfer.<ref name="Verma-2004" />