Progress in molecular biology, large number of known bacterial sequences and a number of microbiological genome sequencing projects finished or running allow to think about creating in vitro the DNA code in order to obtain new metabolites. Here, we describe the attempts of biosynthesis of new polyketides by designing new genes coding polyketide synthases. In assembling new polyketide synthases, the fragments of known genes are widely used. High homology of the polyketide synthase genes and a number of known produced polyketides give a possibility to describe a polyketide synthase on a DNA sequence level. Basing on known amino acid motifs, it is possible to determine enzymatic activities acting in the process of polyketide synthesis, and so to predict putative structure of the final metabolite. Successful artificial synthesis of 6-deoxyerythronolide B synthase genes show how near is the realization of the idea of producing new chemical compounds by creating DNA information.