The chromosomal origin of replication as the basis for the spatio-temporal biology of bacteria

Spatial biology depends on the structural dynamics of the constituents of the cell. We propose that such dynamics during the cell cycle depend to a large extent on the origin of replication and its role in the trajectory of a replication hyperstructure. To explore this ori-Centric view, we adopt both historical and speculative approaches to the initiation of chromosome replication, focusing on Escherichia coli . We relate these approaches to the framework of concepts, results, and procedures within which science is structured; this framework can be considered a paradigm or a “thought style” that sometimes undergoes a major shift. We suggest that a paradigm shift is underway in the study of the cell cycle as shown by the increasing contribution of physical chemistry and, in particular, phase transitions.