A hierarchical model for evolution of 23S ribosomal RNA

The emergence of the ribosome from the 'RNA world', a time when the chemical reactions of primordial life were catalysed by RNA rather than by proteins, was the dawn of the modern DNA- and protein-based world. Konstantin Bokov and Sergey Steinberg propose that even though this event happened about four billion years ago, the structure of the modern ribosome contains clues to its early evolution. Their analysis demonstrates that despite its visible complexity, the structure of 23S rRNA follows a relatively simple hierarchical organizing principle in which, it is argued, the hierarchy is related to the order in which new elements were added to the evolving ribosome as it acquired more protein components.