Polymer-population mapping and localization in the space of phenotypes

We present a mapping between the thermodynamics of an ideal heteropolymer in an external field and the dynamics of structured populations in fluctuating environments. We employ a population model in which individuals may adopt different phenotypes, each of which may be optimal in a different environment. Using this mapping, we develop a path integral formulation for populations and predict the existence of a biological counterpart for the well-known heteropolymer localization phase transition.