What is the Logic of DNA Packing in Bacteria?

Abstract

Before taking a physical chemist’s naive look at DNA in the bacterium, I should like to explain briefly what I mean by the word “logic” in the title of this contribution. The sciences of physics, chemistry and molecular biology are shot through by an interplay between the two types of logic exemplified by our two kinds of computing machine: analogue and digital. These kinds of logic are respectively those of the continuous and the discrete, the measurable and the countable, the deterministic and the probabilistic, the wave and the particle, the potentiometer and the switch. The interplay between them is the result, on the one hand, of the adding up of large numbers of small, discrete events to produce apparently continuous manifestations of them on a larger scale, and, on the other hand, of non-linearities in apparently (better: approximately) continuous systems that result in instabilities or singularities and thus in some phenomenon which appears in a sudden or discontinuous way.