Gene silencing is the prevention of the expression of the gene. When a mutant gene is present in a set of genes, to prevent the malfunction of the mutant gene, cells need to silence or degrade that gene. Gene silencing works either by suppressing transcription or by the RNA degradation process (Transcriptional gene silencing[TGS] and Post-transcriptional gene silencing or RNA interference[RNAi]). TGS mechanism is different from the RNAi mechanism. The consequences of TGS are long-term that can pass on to the daughter cells during cell division, which is not the case in RNAi.