The central role of RNA in the genetic programming of complex organisms

notwithstanding lineage-specific variations, the number and type of protein-coding genes remain relatively static across the animal kingdom. by contrast there has been a massive expansion in the extent of genomic non-proteincoding sequences with increasing developmental complexity. these non-coding sequences are, in fact, transcribed in a regulated manner to produce large numbers of large and small non-protein-coding rnas that control gene expression at many levels including chromatin architecture, post-transcriptional processing and translation. moreover, many rnas are edited, especially in the nervous system, which may be the basis of epigenome-environment interactions and the function of the brain.