Abstract
AbstractA spontaneous symmetry lifting model based on Tlusty's elegant topological deconstruction suggests that multiple punctuated ecosystem resilience regime changes in metabolic free energy that were broadly similar to the aerobic transition enabled a punctuated sequence of increasingly complex genetic codes and protein translators. In a manner similar to the Serial Endosymbiosis effecting the Eukaryotic transition, codes and translators coevolved until the ancestor of the present narrow spectrum of protein machineries became locked-in by evolutionary path dependence at a relatively modest level of fitness reflecting a modest embedding metabolic free energy ecology. The simplest coevolutionary model of code-translator interaction has high and low fidelity quasi-equilibria consistent with the 'virus world' hypothesis of Koonin et al. (2006). A more detailed search for empirical evidence of 'preaerobic' ecosystem shifts in metabolic free energy availability or efficiency of use might be surprisingly fruitful.
Highlights
The genetic code that maps 64 codons to 20 amino acids is far from random, e.g., figure 1 of Koonin and Novozhilov (2009), and the references therein
The question arises as to what drives the dynamics of metabolic free energy, leading to the kind of punctuated ecosystem resilience arguments described by Holling (1973) and Gunderson (2000)
Have the codons undergone evolutionary process, but so too has the translational machinery, as logically implied by the complementary anticodon structure: Recently Sun and Caetano-Anolles (2008) claimed evidence for deep evolutionary patterns embedded in tRNA phylogenies, calculated from trees reconstructed from analyses of data from several hundred tRNA molecules
Summary
The genetic code that maps 64 codons to 20 amino acids is far from random, e.g., figure 1 of Koonin and Novozhilov (2009), and the references therein. In that analysis the optimal code is described by the minimum of a ‘free energy’-like functional, which leads, in his view, naturally to the possibility of describing the code’s emergence as a transition akin to a phase transition in statistical physics The basis for this is the observation that a supercritical phase transition is known to take place in noisy information channels (e.g., Rose, 1998). The second stage of the argument revolves around the relation between intensive indices of metabolic free energy availability – e.g., underlying energy per molecular transaction, and/or efficiency of its use – and R(D), leading to a second free energy-like functional that undergoes another set of punctuated phase changes This second step will be shown to suggest the existence of a metabolic singularity that limits the translation of metabolic free energy into information free energy. The question arises as to what drives the dynamics of metabolic free energy, leading to the kind of punctuated ecosystem resilience arguments described by Holling (1973) and Gunderson (2000)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
