A reappraisal of the plasmid stability problem in chemostat cultures

Segregational instability models of recombinant bacteria conventionally assume that (a) the probability of loss of a unit of a plasmid is constant and (b) upon cell division, the progeny either inherit the mother’s plasmid content entirely or not at all. However, two previous studies have shown that neither assumption is correct. So, in this work, both assumptions have been relaxed to formulate a more general model of plasmid dynamics in a chemostat. Unlike earlier work, this model predicts a time-dependent dilution rate to maximize segregational stability. Some biological implications are discussed.