Published online by Cambridge University Press: 17 March 2009
The code of inheritable information which directs the synthesis of protein molecules is now known. This information is contained in the replicative molecules deoxyribonucleic or ribonucleic acid (Avery, Macleod & McCarty, 1944; Loeb & Zinder, 1961). Translation of the nucleic acid ‘information’ into protein molecules involves the initial transcription of the nucleic acid molecules into transient messenger ribonucleic molecules which are single stranded base paired complements of the more stable ‘information’ nucleic acid molecules. The events leading to the translation of the linear order of nucleic acid information in mRNA to a corresponding linear sequence of amino acids in a protein are largely elucidated at this time and will be the subject of this discussion. Since the knowledge of the genetic code is a result of data obtained from in vitro translational studies which employ the equivalent of mRNA, the genetic code is described as the RNA code rather than its DNA complement. Elucidation of the RNA code has been the focus of research activity for a large number of research laboratories over the past 10–15 years. As a result of these investigations we have a detailed description of the genetic code for life on this planet. This code appears universal in its organization and translational mechanism. Since the interactions of macromolecules necessary for genetic translation are understood with greater precision than the factors responsible for the origin of the Genetic Code, this discussion will deal in more detail with the events in the translation of genetic information.