Self-Referential Formation of the Genetic System [chapter]

Romeu Cardoso Guimarães, Carlos Henrique Costa Moreira, Sávio Torres de Farias
<span title="">2008</span> <i title="Springer Netherlands"> Biosemiotics </i> &nbsp;
Formation of the genetic code is considered a part of the process of establishing precise nucleoprotein associations. The process is initiated by tRNA dimers paired through the perfect palindromic anticodons, which are at the same time codons for each other; the amino acid acceptor ends produce the transferase function, in a manner similar to the reaction occurring in ribosomes. The connections between nucleic acids and proteins are bidirectional, forming a self-feeding system. In one
more &raquo; ... proteins that are resistant to degradation and efficient RNA-binders stabilize the tRNAs that are specifically involved with their production; in the other direction, these tRNAs become fixed with the correspondences which are the amino acid codes. Replication of the stabilized tRNAs becomes elongational, forming poly-tRNAs, the precursors of the mRNA strings (genes), and of ribosomes. The linear order in the gene sequences follows the temporal succession of the encoding of tRNA pairs. The whole encoding process is oriented by the tRNA pairs. The core sequence of proteins shows the predominant aperiodic conformation and the anticodonic principal dinucleotides (pDiN) are composed of two purines or two pyrimidines: (1a) Gly / Pro; (1b) Ser / Ser; (2a) Asp, Glu / Leu; (2b) Asn, Lys / Phe. Members of the following pairs, with pDiN composed of a purine and a pyrimidine [(3a) Ala / Arg; (3b) Val / His, Gln; (3c) Thr / Cys, Trp; (4) Ile, Met / Tyr, and iMet / Stop], are added, respectively, to the mRNA heads / tails. It is indicated that: (a) The Last Universal Common Ancestor populations could, at some early stages, be composed of lineages bearing similar genetic codes, due to the simple and highly deterministic character of the process; (b) Genetic information was created during the process of formation of the coding/decoding subsystem, inside a proto-metabolic system already producing some amino acids and tRNA-like precursors; (c) Genes were defined by the proteins that stabilized the system, as memories for their production.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="">doi:10.1007/978-1-4020-6340-4_5</a> <a target="_blank" rel="external noopener" href="">fatcat:m737nov2ybdhhlnbkbehpbobyu</a> </span>
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