Figure 41-3: Comparison of the genetic switch regions of bacteriophages g1e (A), lambda (B) and A2 (C) (drawn to scale). The operator sequences (O(1) to O(6)) are enclosed in shaded boxes. The –10 and –35 promoter consensus regions are indicated by open boxes. The transcription start sites of the divergently oriented promoters are signaled by bent arrows. The numbers within the double headed arrows indicate the lengths (in bp) of the relevant features as follows (from top to bottom): distance between operator sequences, operators, segment from center to center of contiguous operators, stretch between the centers of the P(L) and P(R) promoters; note especially the difference in the size of the segments located between the operator sites and the total length of the P(L) – P(R) intervening sequence. In the case of g1e another operator sequence was detected 3’ of each cpg and cng (which are the functional equivalents to cI and cro respectively).