  Recent experimental and theoretical approaches have attempted to quantify the
physical organization (compaction and geometry) of the bacterial chromosome
with its complement of proteins (the nucleoid). The genomic DNA exists in a
complex and dynamic protein-rich state, which is highly organised at various
length scales. This has implications on modulating (when not enabling) the core
biological processes of replication, transcription, segregation. We overview
the progress in this area, driven in the last few years by new scientific ideas
and new interdisciplinary experimental techniques, ranging from high space- and
time-resolution microscopy to high-throughput genomics employing sequencing to
map different aspects of the nucleoid-related interactome. The aim of this
review is to present the wide spectrum of experimental and theoretical findings
coherently, from a physics viewpoint. We also discuss some attempts of
interpretation that unify different results, highlighting the role that
statistical and soft condensed matter physics, and in particular classic and
more modern tools from the theory of polymers, plays in describing this system
of fundamental biological importance, and pointing to possible directions for
future investigation.
