Posterior to the discovery of the double-stranded RNA mediated gene silencing two decades ago, RNA interference or RNA-mediated gene silencing has received unusual intensity of study in the biology-related research fields. RNA silencing represents a large spectrum of gene regulation mechanisms in all kingdoms of eukaryotes. The power and necessity of RNA silencing has been unambiguously appreciated in both animals and plants, although the mechanisms engaged are divergent in some aspects. Interestingly, as comprehensively reviewed by Schumann et al. in this issue, RNA silencing in the simple eukaryotic fungi strikingly differs from those of animals and plants, and among fungal species as well.