Team leader: Wei Tian
We study small RNAs which play critical roles in the regulation of many biological processes in most eukaryotes. MicroRNAs, endogenous siRNAs and Piwi-interacting RNAs are three major classes of small RNAs. We mainly focus on microRNAs, which interact with target mRNAs by base paring to induce mRNA cleavage or translation inhibition. By deep sequencing and computational analysis, we detect and profile both known and novel microRNAs at unprecedented sensitivity. Most microRNAs are highly conserved across closely related species, and some even show conservation between invertebrates and vertebrates. The origin of new microRNA genes and their subsequent evolution is rarely unknown. We also try to explore the origin of these newly emerged microRNA genes in the human lineage.