On the origin of biological information

Abstract

The term biological information comprises not only genetic information, but also the “blueprint” information that is contained in cellular entities such as membranes or organelles. Also these entities are multiplicated during growth and passed on to daughter cells together with the genetic material. The assembly of a first cell would therefore require the presence of numerous preformed structures in addition to the genetic material. Here I shall focus only on the prebiotic origin of genetic information. I shall demonstrate that, in principal, a flow of information from proteins → RNA → DNA is possible, although it appears to violate the “central dogma” of molecular biology. Two known enzymes are required to model such a process: (1) Qs replicase, an enzyme that can act both as a template-free RNA polymerase forde novo RNA synthesisand as an RNA-dependent RNA replicase. (2) A reverse transcriptase acting as an RNA-dependent DNA polymerase. Of significant interest are the properties of Qs replicase. Could a prebiotic precursor of Qs replicase have served for thede novo synthesis of precursor RNA? The extremely complex subunit structure of Qs replicase appears to rule out any link to the prebiotic world. Nevertheless, the thermal polymerization of selected amino acid mixtures has yielded a huge variety of catalytically active products. Among these are also polymers that exhibit a weak nucleotide oligomerase activity. This observation demonstrates that a flow of information from prebiotic amino acid polymers to RNA or its precursors is principally possible.