In his analysis of rII in phage, Benzer assayed complementation. Suppose you try your hand at this with several mutants and get the following results (+ = complementation): 42 and 62 +
42 and 83 -
62 and 63 -
62 and 74 +
42 and 74 -
42 and 75 +
62 and 75 -
Mutation 42 has previously been shown to be in a different gene than mutation 62. What can you conclude?
A)Mutations 42 and 75 are in the same gene.
B)Mutations 62 and 74 are in the same gene.
C)Mutations 62, 63, and 74 are in the same gene.
D)Mutations 42 and 74 are in the same gene.
E)Mutation 63 is not in the same gene as either 62 or 42.

Question

Quizplus · Accepted Answer

Mutations 42 and 74 complement each other (+), indicating that they are in different genes. Mutations 62 and 74 also complement each other (+), indicating that they are in the same gene. Similarly, mutations 42 and 75 complement each other (+), indicating that they are in the same gene. Mutations 62 and 63 do not complement each other (-), indicating that they are in the same gene as each other but in a different gene from mutations 42 and 74. Therefore, the correct conclusion is that mutations 42 and 74 are in the same gene, while mutations 62, 63, and 74 are in a different gene from mutation 42.

In His Analysis of RII in Phage, Benzer Assayed Complementation