Figure 2.

Removable gene sets of the phages. (A) The frequencies of mutation (deletion and disruption) of genes in the removable gene sets of the phages T7, seszw, T4 and selz were measured in the mutant phage populations obtained at the nth transfer (T, transfer; n, number of transfers) generated by the two types of plasmid libraries (cassette-gene and cassette-100). The frequency represents the percentage (log₂) of the corresponding reads of the gene (deleted or disrupted) in the population; accordingly, heatmaps were generated by the pheatmap R package. ‘L’ denotes the deletion of a large fragment that we did not design; ‘P’ denotes the premature termination codons in the coding regions that cause gene disruption by one- or two-base deletions. (B) Scatter plots of the average frequencies of the mutated genes in the two types of plasmid libraries. The Pearson correlation coefficients (r) of the frequencies for the two types of libraries and the P-values (p) were calculated using SPSS software. Each blue circular ring represents a gene in the removable gene set. The red lines are y–x regression lines for the frequencies of mutated genes. (C) Venn diagrams showing the overlap of the removable gene sets detected by the two types of libraries with the gene set that we designed for mutation.