Does the Ribosome Challenge our Understanding of the RNA World?

  title={Does the Ribosome Challenge our Understanding of the RNA World?},
  author={Anthony M. Poole and Daniel C. Jeffares and Marc P. Hoeppner and David Penny},
  journal={Journal of Molecular Evolution},
AbstractIn a recent article published in these pages, Bowman and colleagues propose that the ribosome represents a challenge to the RNA world model, a long-standing framework to explain the origin of DNA and genetically encoded proteins from a hypothetical RNA-based system. Specifically, they outline a scenario for the emergence and subsequent coevolution of the peptidyl transferase centre (PTC) of the ribosome with non-templated peptide products of this RNA through chemical evolution. They… 

Possible Emergence of Sequence Specific RNA Aminoacylation via Peptide Intermediary to Initiate Darwinian Evolution and Code through Origin of Life

It is concluded that translation should have emerged at the same time when the standard genetic code begun to evolve due to the stabilizing effect on RNA-peptide complexes with the help of BPs.

A ribonucleopeptide world at the origin of life

This review covers the most recent and relevant scientific investigations that propose a better understanding of the ribonucleopeptide world hypothesis and the appearance of life and proposes two hypotheses for a primitive translation machinery that might have been formed of either a T box ribozyme or a ribopolymerase.

Clues to tRNA Evolution from the Distribution of Class II tRNAs and Serine Codons in the Genetic Code

It is proposed that the class II tRNA structure of tRNASer and the arrangement of serine codons in the genetic code provide clues to the early evolution of tRNA and the Genetic code.

Emerging Frontiers in the Study of Molecular Evolution

A collection of the editors of Journal of Molecular Evolution have gotten together to pose a set of key challenges and future directions for the field of molecular evolution. Topics include

Functional innovation from changes in protein domains and their combinations.

Physiological and proteomic analyses reveals that brassinosteroids application improves the chilling stress tolerance of pepper seedlings

The physiochemical analysis showed that EBR treatment improved the tolerance of pepper seedlings to chilling stress, and up-regulated DEPs were associated with the photosynthetic electron transfer chain, oxidative phosphorylation, GSH metabolism pathway, Calvin cycle and signaling pathway.



The Path from the RNA World

A sequential (step by step) Darwinian model for the evolution of life from the late stages of the RNA world through to the emergence of eukaryotes and prokaryotes, with a functional explanation that proKaryote ancestors underwent selection for thermophily and/or for rapid reproduction at least once in their history.

Relics from the RNA World

The model as developed serves as an outgroup to root the tree of life and is an alternative to using sequence data for inferring properties of the earliest cells.

The transition from noncoded to coded protein synthesis: did coding mRNAs arise from stability-enhancing binding partners to tRNA?

This model proposes that genetic coding arose de novo from complementary base pair interactions between tRNAs and single-stranded RNAs present in the immediate environment.

Modern mRNA Proofreading and Repair: Clues that the Last Universal Common Ancestor Possessed an RNA Genome?

It is concluded that a strong case can be made that the Last Universal Common Ancestor (LUCA) possessed a repair-competent RNA polymerase, which would have been capable of acting on an RNA genome.

An Overview of the Introns-First Theory

There is strong evidence against introns being uncommon in the last eukaryotic common ancestor (LECA), and expanding only within extant eUKaryotic groups—the ‘very-late’ intron invasion model.

Early evolution: prokaryotes, the new kids on the block.

It is argued here that the ribosome (together with the RNAs involved in its assembly) is so large that it must have had a prior function before protein synthesis, which can explain many steps in the origin of life while accounting for the observation that eukaryotes have retained more vestiges of the RNA world.

The origin of RNA and "my grandfather's axe".

The driving force for molecular evolution of translation.

It is suggested that the availability of even simple peptides could have significantly enlarged the otherwise limited structure space of RNA and contributed to the structural capabilities of the RNA world.

In-ice evolution of RNA polymerase ribozyme activity.

In vitro evolution of catalysts directly in the RNA-stabilizing medium of water ice yielded RNA polymerase ribozymes specifically adapted to sub-zero temperatures and able to synthesize RNA in ices at temperatures as low as -19 °C, an important stepping stone towards RNA self-replication.

Evolutionary implications of error amplification in the self-replicating and protein-synthesizing machinery

It is shown that the constraints on mitochondrial tRNA in fungi are not as relaxed as those in animals, since at least one protein of the mitochondrial ribosome is coded for in the mitochondrial genome of fungi.