The various strategies of codon decoding in organisms of the three domains of life: evolutionary implications.

Abstract

Over a thousand of cytoplasmic, non organellar tRNA genes were extracted from the whole-genomes of more than 100 organisms spanning the Bacteria, Eukarya and Archaea (tRNomics). Also, whenever possible, the genes coding for modification enzymes acting on tRNA, particularly those involved in modification of nucleotides in the anticodon loop, were identified (Modomics). Combining these two data sets, we were able to reveal three main decoding strategies used by individual contemporary organisms to read the 62 (61+1 initiator) sense codons of mRNA. Based on the known phylogenetic relationships of the different organisms analyzed, this work allows to predict which RNA modification enzymes are essential for an accurate and efficient translation process, as well as to shed light on when these complex and diverse tRNA maturation processes probably emerged during cellular evolution.