Abstract:RNA interference (RNAi) refers to the gene silencing phenomenon induced by double-stranded RNAs. The RNAi mechanism is well conserved from plants to animals. It plays important roles in many important biological processes, such as antisense response, transposon repression and development regulation. RNA interference is also an important tool for gene function study and gene therapy. Due to the importance of RNA interference, two American scientists, Andrew Z. Fire and Craig C. Mello, were awarded the Nobel Prize in Physiology or Medicine of 2006 for their contribution in the discovery of RNA interference.