Invited Talk Landscapes in RNA folding and evolution

The landscape concept is an old metaphor used by Sewall Wright to illustrate the evolution of species in analogy to an adaptive walk on an abstract fitness landscape. Two success-ful experimental approaches turned the metaphor into a powerful concept for studies on evolution of molecules and biopolymer folding: (i) In vitro evolution and selection experi-ments, mainly with populations of RNA molecules, provides insight into the distribution of fitness values in sequence space, and (ii) conformational energy landscapes, invented and first used for small molecules in quantum chemistry and spectroscopy, were extended by means of empirical parameters to successful computations of energies and free energies of biopolymers. Theoretical investigations of biopolymer landscapes were encouraged by the fast and straightforward computation of RNA secondary structures and, therefore, most of the currently available exact results deal with RNA folding or RNA evolution. New tech-niques, which are suitable for studying landscapes on discrete spaces, were developed and successfully applied to RNA and model proteins. The lecture presents an overview of the state of the art in calculations of RNA conformational landscapes and reviews RNA opti-mization through adaptive walks of populations in sequence space. Finally, we address th