  In this brief article I show how the notion of coarse graining and the
Renormalization Group enter naturally in the dynamics of genetic systems, in
particular in the presence of recombination. I show how the latter induces a
dynamics wherein coarse grained and fine grained degrees of freedom are
naturally linked as a function of time leading to a hierarchical dynamics that
has a Feynman-diagrammatic representation. I show how this coarse grained
formulation can be exploited to obtain new results.
