Figure 1.

(A) Computed maximum phage doubling rate, μ_m, as the gene 1 element is repositioned on the wild-type T7 genome (B). ●, μ_m at the 5′ end of the gene 1 element for 72 positional mutants. ⧫, The computed μ_m for the ectopic gene 1 strains that we constructed and characterized experimentally. ▴, The μ_m computed for wild type. (B) The wild-type T7 (T7⁺) genome. Boxes represent coding regions (genes are numbered as space permits), vertical lines with half bars represent E. coli (blue) and T7 (green) promoters; bar height is proportional to the observed or estimated strength of each promoter. The transcriptionally inactive T7 promoters, øOL and øOR, are shown in black. E. coli RNAP (TE) and T7 RNAP (Tø) terminators are shown as vertical lines with full bars. RNase III recognition sites are shown as vertical lines below the genome. As the genome is normally depicted, all transcription goes from left to right. The positions of the gene 1 element in the strains constructed and characterized in the laboratory are shown below the genome. (C) A random T7 permutation mutant that has a computed μ_m 21% above T7⁺.