RNA: An Expanding View of Function and Evolution

Supplement Aims and Scope have suggested that structural conservation in these lincRNAs may have been retained, despite the apparent lack of sequence conservation. These recently identified non-coding RNAs represent an evolutionary history different from that of the protein coding genes, which remains to be explored. The function and evolution of alternative splicing § § Alternative splicing tremendously diversifies transcriptomes among organisms, even when their repertoires of protein coding genes are similar. The fast improvement on read length of NGS technologies will render a more thorough and unambiguous identification of alternative splice forms. Such resources could serve as the basis for exploring conservation and divergence of splicing events among organisms. They could also facilitate studies on the function of splicing events specific to certain organisms. RNA-seq of non-model organisms for § § phylogenomic studies RNA-seq approaches enabled de novo identification of genes from organisms of no assembled genome sequences. Analyzing such extensive list of genes will result in better resolution of organism phylogeny. In addition, by comparing gene sequences among a wide range of organisms, many intriguing evolutionary questions may be addressed. For instance, how frequently genome duplication has happened in a certain taxon? How frequently horizontal gene transfer has happened between symbiotic organisms or parasites and hosts? Next generation sequencing (NGS) technologies have enabled unprecedentedly deep characterization of transcriptomes. Compared to the microarray technology, NGS has been a much more favorable method for transcriptome profiling, as it doesn't require any pre-existing knowledge of the transcrip-tome of any given species. By sequencing transcriptomes to enough depth, several studies have reported a remarkably large number of novel RNA species and/or previously undetected splice forms. An inclusive identification of genes for organisms without genome information is also within reach. With intricate designs, it is even possible to specifically sequence the double-stranded portion of RNAs, such that the secondary structure of these RNAs could be inferred. Such comprehensive elucidation of transcriptomes has opened many new venues for studies on the function and evolution of the diverse RNA repertoire. The current supplement aims to serve as a portal to report original studies and summarize progress in this fast-moving area. Novel RNA species discovered by NGS and their § § unique evolutionary history Genome-wide studies utilizing NGS technologies have uncovered novel types of RNAs, such as lncRNA, circular RNA and spliRNA. Many of these novel RNA species have been reported to play important regulatory roles. With …