ERROR PREVENTION AND MITIGATION AS FORCES IN THE EVOLUTION OF GENES AND GENOME

 

 

Faithful transmission of information is crucial for life. This is perhaps most evident when genetic instructions are passed on from parents to their offspring. If the information is corrupted at this stage, the result depending on the sequence affected may be lethal. Arguably the most extensive support for a role of error prevention in the evolution of gene anatomy comes from the study of synonymous codon usage^1, and also the the translation error (TE) model for evolution of the codon catalogue deals reveals about the necessity of minimizing the effects of translation errors^2.

The genetic code has the remarkable property of error minimization, whereby the arrangement of amino acids to codons is highly efficient at reducing the deleterious effects of random point mutations and transcriptional and translational errors^3. The elucidation of nonsense-mediated decay (NMD) as an RNA surveillance system is a relatively recent event. Studies in yeast and other model organisms have enumerated specific molecular details that provide some insight into mechanisms whereby a transcript that contains a premature termination codon (PTC) is recognized by NMD factors and rapidly degraded, thus eliminating abnormal transcripts^4.

Frame-shifting errors are the major type errors costs of mis-elongation and frame-shifting errors, that differences in translational robustness between the 5’ and 3’ ends of genes should be less pronounced in genomes with higher GC content^5. In the meanwhile the Chaperons type molecular protein (GroEL protein) affects codon usage and prevent both newly synthesized polypeptide chains and assembled subunits from aggregating into nonfunctional structures^6.

Key words: Mitigation, Translation error, PTC, NMD, Chaperons

References:

1. Nina Stoletzki and Adam Eyere-Walker., 2007, Synonymous codon usage in E coli: Selection for Translational accuracy. Mol. Biol. Evol. 24(2):374-381.

2. Woese, C.R., 1965, On the evolution of the Genetic Code. Nature. 54, 71.

3. Steven E.M., 2008, A neutral origin of error minimization in the Genetic code. J Mol. Evol. 67:510-516.

4. Mehrdad Khajavi, Ken Inoue and James R.L., 2006, Nonsense-mediated mRNA decay modulates clinical outcome of genetic disease. European J. Human Genetics, 14:1074-1081.

5. Tobias Warnecke, Yang Huang, Teresa, M.P and Laurence D.H., 2010, Unique cost dynamics elucidate the role of frameshifting errors in translational robustness. Genome Biol. Evol. 2:636-645.

6. Tobias Warnecke and Laurence D.H., 2010, GroEL dependency affects codon usage- support for critical role of misfolding in gene evolution. Mol. Systems Biol. 6:340.