This is list is currently comprised of Pseudomonas transposon insertion sites obtained from 3 different comprehensive transposon mutant libraries (two in P. aeruginosa PAO1 and one in PA14). If you are interested in finding genes that do not have transposon insertions (e.g. are putatively essential), 1) Go to the advanced search page, 2) Start typing strain name in the first text box (entitled "Start typing and select a strain from the list (optional)”) and select the appropriate choice. 3) Select “Only show annotations without mutants” from the “Filter transposon mutants” dropdown list under the “Filter results” section.