HIVEP2-DT and cystic fibrosis: The list of commonly lost or mutated genes also included other genes known to be targeted by selection during long-term evolution in the CF lung (22, 25, 39): O-antigen biosynthesis (hisF2H2, wzx, and wzy), type III secretion system (T3SS) (exsD), exotoxin A (xqhB), and twitching motility (pilA).