Saint-Léger, AdélaïdeBello, Carla, 1990-Dans, Pablo D.Gabriel Torres, AdrianNovoa, Eva MariaCamacho, NoeliaOrozco, ModestoKondrashov, Fyodor A., 1979-Ribas de Pouplana, Lluís2017-01-262017-01-262016Saint-Léger A, Bello Cabrera C, Dans PD, Gabriel Torres A, Novoa EM, Camacho N, Orozco M, Kondrashov FA, Ribas de Pouplana L. Saturation of recognition elements blocks evolution of new tRNA identities. Science Advances. 2016;2(4):e1501860. DOI: 10.1126/sciadv.15018602375-2548http://hdl.handle.net/10230/27999Understanding the principles that led to the current complexity of the genetic code is a central question in evolution. Expansion of the genetic code required the selection of new transfer RNAs (tRNAs) with specific recognition signals that allowed them to be matured, modified, aminoacylated, and processed by the ribosome without compromising the fidelity or efficiency of protein synthesis. We show that saturation of recognition signals blocks the emergence of new tRNA identities and that the rate of nucleotide substitutions in tRNAs is higher in species with fewer tRNA genes. We propose that the growth of the genetic code stalled because a limit was reached in the number of identity elements that can be effectively used in the tRNA structure.application/pdfeng2016 © The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). 10.1126/sciadv.1501860info:eu-repo/semantics/articlehttp://dx.doi.org/10.1126/sciadv.1501860TRNA identitiesGenetic codeEvolutionADATTRNA glyinfo:eu-repo/semantics/openAccess