Equipartition and other modes of partition: on the interpretation of curing kinetics using rep(ts) plasmids.

One method that has been used to determine the mode of distribution (partition) of bacterial plasmids at cell division is analysis of the kinetics of appearance of plasmid-free cells during exponential growth at a temperature that is non-permissive for the replication of a rep(ts) plasmid. Such an experiment was used by Hashimotoh-Gotoh and Ishii (1982) as the basis for proposing a new model, the Single-Site-Inheritance Model. I claim that this method does not give conclusive results unless the copy number distribution at cell division is known. This distribution can be broad because of the properties of the replication control system and not only because of randomness in partition.