  We address the question, related with the origin of the genetic code, of why
are there three bases per codon in the translation to protein process. As a
followup to our previous work, we approach this problem by considering the
translocation properties of primitive molecular machines, which capture basic
features of ribosomal/messenger RNA interactions, while operating under
prebiotic conditions. Our model consists of a short one-dimensional chain of
charged particles(rRNA antecedent) interacting with a polymer (mRNA antecedent)
via electrostatic forces. The chain is subject to external forcing that causes
it to move along the polymer which is fixed in a quasi one dimensional
geometry. Our numerical and analytic studies of statistical properties of
random chain/polymer potentials suggest that, under very general conditions, a
dynamics is attained in which the chain moves along the polymer in steps of
three monomers. By adjusting the model in order to consider present day genetic
sequences, we show that the above property is enhanced for coding regions.
Intergenic sequences display a behavior closer to the random situation. We
argue that this dynamical property could be one of the underlying causes for
the three base codon structure of the genetic code.
