Figure 2.

Apparent stability of plasmids with the EcoRV RM gene complex and its mutant versions. During repeated batch culture (10⁶-fold dilution and overnight incubation) in the absence of any selective antibiotics, aliquots were assayed on LB agar plates with and without Ap. The ratio of these colony counts was taken as the fraction of cells carrying the plasmid. The generation number was estimated from the colony counts on LB agar. □, pBR322; ▵, pYNEC113 (R⁺ M⁺ C⁺); ○, pYNEC117 (R^- M⁺ C⁺); and ◊, pYNEC118 (R⁺ M⁺ C⁻).