RNA interference is essential for the

bRNAi is a regulatory mechanism for an estimated $30 \%$ of all protein-coding genes(in mammals). It helps to protect cells against certain viruses by targeting viral RNA for destruction. It helps to silence potentially disruptivetransposons in the genome by destroying RNA copies arising from transposon replication.RNAi is a precise and efficient tool for knockout of specific genes when studying gene function in experimental organisms. It also has potential for new forms of targeted gene therapy.