RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules, and won 2016 Nobel Prize in Physiology or Medicine. RNAi has become a highly efficient research tool, both in cell culture and in living organisms, because synthetic dsRNA introduced into cells can selectively and robustly induce suppression of specific genes of interest. RNAi can be used for large-scale screens that systematically shut down each gene in the cell, which can help to identify the components necessary for a particular cellular process or an event such as cell devision. The pathway is also used as a practical tool in biotechnology, medicine, and insecticides.

Small interfering RNA (siRNA, ~ 21 nt dsRNA) can cause degradation of the target gene mRNA that matches the sequence, resulting in a gene-silenced phenotype in the cell or organism.