The broad, long-term objective of the proposed research is to address questions concerning the origin of function from biopolymers. The scope of this proposal will be two fold: 1) Develop a method of generating a large ex vivo population of naive (unselected) RNA-polypeptide fusions. 2) Use this population as a system to study the origins of biocatalysis, specifically to probe the abundance of a simple binding function among sequences of the major biopolymers, RNA, RNP (ribonucleoprotein complexes), and proteins. By examining the density of simple functions found in large random populations of RNA, protein, and ribonucleoprotein complexes it will be possible to estimate how likely a given function could arise and propose a path for the evolution of that function.