A small informal symposium on "Molecular Genetics" was organized by us on behalf of the "Gesellschaft Deutscher Naturforscher und Arzte" and took place in Berlin in October 1967. There were about 40 partici pants from Europe and the United States. Molecular Genetics represents today an extraordinarily comprehensive research field. Therefore the organizers of the symposium had the choice either of limiting the meeting to a particular topic or of covering a wider selection of current problems. The latter alternative was chosen. The fields of research of the participants covered the broad range of scientific problems in which molecular genetics is nowadays involved: Genetic code; chemistry and biosynthesis of proteins; mutation, modification and reactivation of nucleic acids; biochemistry of regulation; comple mentation; structure; replication and function of viruses, etc. The meeting took place in the Hotel Schweizerhof where the partici pants were also accommodated. This permitted close contact between the participants outside of the official program and allowed informal discussions, which started during the meetings, to be continued after wards. Owing to the informal nature of these discussions, only a part of them could be included in this book. Berlin, September 1968 H. G. WITTMANN H. SCHUSTER Contents List of Participants . . . . . . . . . . .... VII I. Structure and Function of Ribosomes; Complementation Complementation and Dominance Relationsship between Protein Subunits. By J. R. S. FINCHAM. . . . . . . . . . . . . . . Ribosomal Proteins of E. coli and Yeast. By E. KALTSCHMIDT, V. RUDLOFF, G. STOFFLER, A. CHERSI, M. DZIONARA, D. DOl\IIER, and H. G. WITTMANN . . . . . . . . . . . . . . .. . . 5 ."