The short-time dynamics of bacterial chromosomal loci is a mixture of
subdiffusive and active motion, in the form of rapid relocations with
near-ballistic dynamics. While previous work has shown that such rapid motions
are ubiquitous, we still have little grasp on their physical nature, and no
positive model is available that describes them. Here, we propose a minimal
theoretical model for loci movements as a fractional Brownian motion subject to
a constant but intermittent driving force, and compare simulations and
analytical calculations to data from high-resolution dynamic tracking in E.
coli. This analysis yields the characteristic time scales for intermittency.
Finally, we discuss the possible shortcomings of this model, and show that an
increase in the effective local noise felt by the chromosome associates to the
active relocations.Comment: 8 pages, 6 figures; typos added, introduction expanded, conclusions
unchange
