A Study on RNA and Protein Structures Peter Schuster and Peter F. Stadler Mapping sequences onto biopolymer structures is characterized by redundancy since the numbers of sequences exceed the numbers of structures. The degree of Redundancy depends on the notion of structure. Two classes of biopolymers, RNA molecules and proteins are considered in detail. A general feature of sequence to structure mappings is the existence of a few common and many rare structures. Consequences of redundancy and frequency distribution of RNA structures are shape space covering and the existence of extended neutral networks.
Populations migrate on neutral networks by a diffusion-like mechanism.
Neutral networks are of fundamental importance for evolutionary optimization since they enable populations to escape from local optima of fitness landscapes.