RNA interference is a biological process in which RNA molecules inhibit gene expression or translation. This is done by neutralising targeted mRNA molecules.
A simplified model for the RNAi pathway is based on two steps, each involving ribonuclease enzyme. In the first step, the trigger RNA (either dsRNA or miRNA primary transcript) is processed into a short interfering RNA (siRNA) by the RNase II enzymes called Dicer and Drosha. In the second step, siRNAs are loaded into the effector complex RNA-induced silencing complex (RISC). The siRNA is unwound during RISC assembly and the single- stranded RNA hybridizes with mRNA target. This RNAi is seen in plant feeding nematodes.