A series of methods that utilize the incremental truncation of nucleic acids are described to create a plurality of modified nucleic acids and hybrid polypeptides. A plurality of substantially all possible single base-pair deletions of a given nucleic acid sequence is created. A method of making shuffled incremental truncated nucleic acids, which is independent of nucleic acid sequence homology, is also described. These methods can be used in protein engineering, protein folding, protein evolution, and the chemical synthesis of novel hybrid proteins and polypeptides.