iGenetics 3rd Edition by Peter Russell

Exercise 10

Upon infection of E. coli with bacteriophage T4, a series of biochemical pathways result in the formation of mature progeny phages. The phages are released after lysis of the bacterial host cells. Suppose that the following pathway exists:
Suppose also that we have two temperature-sensitive mutants that involve the two enzymes catalyzing these sequential steps. One of the mutations is cold sensitive ( cs ), in that no mature phages are produced at 17°C. The other is heat sensitive ( hs ), in that no mature phages are produced at 42°C. Normal progeny phages are produced when phages carrying either of the mutations infect bacteria at 30°C. However, let us assume that we do not know the sequence of the two mutations. Two models are therefore possible:
Outline how you would determine experimentally which model is the correct model without artificially lysing phage-infected bacteria.