Mutations in genes cI, cII, cIII would affect lysogeny. cI gene encodes for repressor protein, cII gene encodes an activator of PRE, and cIII encodes a protein that protects cII from degradation. Mutations in anti-terminator region N would also affect lysogeny as its function is required for transcription of the cII and cIII genes, but it is also necessary for genes involved in lysis. Mutations in the gene encoding the integrase (int) would also affect the ability of a mutant phage to lysogenize.