A solvable model of the genesis of amino-acid sequences via coupled   dynamics of folding and slow genetic variation
  We study the coupled dynamics of primary and secondary structure formation (i.e. slow genetic sequence selection and fast folding) in the context of a solvable microscopic model that includes both short-range steric forces and and long-range polarity-driven forces. Our solution is based on the diagonalization of replicated transfer matrices, and leads in the thermodynamic limit to explicit predictions regarding phase transitions and phase diagrams at genetic equilibrium. The predicted phenomenology allows for natural physical interpretations, and finds satisfactory support in numerical simulations. 
S. Rabello, A.C.C. Coolen, C.J. Perez-Vicente, and F. Fraternali