Experimental evolution of <i>S.</i> Typhimurium <i>hns</i> mutants.

<p>(A) An <i>hns</i> mutant isolate prepared for microarray analysis incurred a spontaneous 10 kb deletion after minimal laboratory passage. The white arrows represent the deleted open reading frames (ORFs) and the black arrows represent the ORFs adjacent to the deleted region. (B) Schematic diagram illustrating the experimental design of the serial passaging experiment. Six independently derived <i>S.</i> Typhimurium <i>hns</i> mutant colonies were selected to initiate cultures of LB media, named <i>Δhns</i> lineages A–F. The <i>Δhns</i> lineages were serially passaged in parallel with six wild type cultures for 30 days (approx. 300 generations) and samples from each lineage were stocked daily. Genomic DNA from each population at Day 1 and Day 30 of the evolution period was prepared for Illumina sequencing. (C) Left hand side: growth curves of the <i>hns</i> mutant populations at day 1 (green curves) and day 30 (red curves) of the evolution period. Right hand side: growth curves of the wild type populations at day 1 (blue curves) and day 30 (grey curves) of the evolution period. Liquid growth assays were performed in a 96-well plate reader.