Acta Biológica Colombiana
Print version ISSN 0120-548X
ANDRADE, EUGENIO. The Analog Digital Duality of Information is Exemplified by Studying RNA Molecules. Acta biol.Colomb. [online]. 2011, vol.16, n.3, pp. 15-42. ISSN 0120-548X.
The study of RNA molecules have contributed to formalizing the physical notion of information considered in its dual nature analog and digital. The central dogma of molecular biology restricts the notion of information to its digital aspect and so to copying fidelity of symbol’s string during replication (DNA-DNA) and transcription (DNA-RNA), and also in translation to proteins, by means of a genetic code. This vision leads to the paradox about what molecule came first, DNA or proteins, that is solved by the hypotheses that postulates the existence of prebiotic RNA prior to the emergence of genetically encoded proteins and DNA. This hypothesis is based on solid empirical findings such as the discovery of catalytic RNA and RNA structures highly conserved in evolution and found in all living organisms. Besides, experimental models inspired on virus RNA replication and computational models that deal with the relations between secondary planar structures and linear sequences, confirm the advantages of RNA molecules to understand the origin of genetic information, due to their decisive role in the emergence of the genetic code, their functional role in gene expression, their structural plasticity and the accessibility of functional structures from any arbitrary sequence that undergoes cycles of mutation and selection. To state that the emergence of digital information requires the prior existence of analog information, not only contributes to solve specific problems of biology, but mainly contributes to advance in the understanding the physical meaning of the two different information measurements proposed by Claude Shannon and Gregory Chaitin.
Keywords : RNA; DNA; Protein; digital information; analog information; central dogma; RNA world.