Non-micro-short RNAs: the new kids on the block

The advent of ultra-high-throughput sequencing has led to the discovery of a large group of small, noncoding RNAs that are not microRNAs. The functional relevance of microRNAs has been well established over the last decade. In this Perspective, we focus on the non-micro-short RNAs that comprise a variety of functional classes and range from 16-40 nucleotides in size. We will highlight how some of these non-micro-short RNAs were discovered, as well as their biogenesis, potential mechanisms of action, and role in diverse biological processes, development, and disease. Finally, we will describe what must be done to further our understanding of these enigmatic molecules.