ABSTRACT
This chapter considers the possibility that new biological activities can be selected from cells harboring populations of random nucleotide sequences. It reviews the initial attempts at selecting new active molecules from random DNA sequences and considers future possibilities for using this technique. The chapter analyzes the feasibility of selecting new biological activities from random nucleotide sequences and it considers restrictions in the selective processes that might have occurred during prebiotic evolution. In order to select biologically active DNA sequences from populations of random DNA, one desires a short segment of DNA that both encodes a selectable biological activity and can tolerate nucleotide substitution at high frequency. The technique of selecting biologically active DNA sequences from large random populations provides a new method for identifying nucleotide sequences with unique functions. The ultimate challenge of genetic engineering with random sequences will be the construction of completely new enzymes.
