Generation times: Ancestral dependence and dependence upon cell size

Abstract

Earlier generation time data and records for E. coli B r were reexamined, and confirm and extend evidence that the generation times of cells are dependent upon those of their ancestors for a period of three generations. The generation times of individual cells show significant negative correlations with the mean generation times of two or more successive generations in their ancestral or progeny lines. In addition, the relationships between the lengths of these cells at birth and their final lengths at division show that the permissible ranges for the generation times of daughter cells are determined by the final lengths of their parent at division. When considered with the absence of a significant correlation between mothers and daughters and the absence of significant correlations between other pairs of single cells in a progeny line, these results require that generation times are affected by at least two compensatory factors transmitted through the cytoplasm from mother to daughter. These results are in disagreement with some assumptions of all known models for generation time distributions.