Drosophila genome-wide RNAi screens: are they delivering the promise?

The emergence of RNA interference (RNAi) on the heels of the successful completion of the Drosophila genome project was seen by many as the ace in functional genomics: Its application would quickly assign a function to all genes in this organism and help delineate the complex web of interactions or networks linking them at the systemic level. A few years wiser and a number of genome-wide Drosophila RNAi screens later, we reflect on the state of high-throughput RNAi screens in Drosophila and ask whether the initial promise was fulfilled. We review the impact that this approach has had in the field of Drosophila research and chart out strategies to extract maximal benefit from the application of RNAi to gene discovery and pursuit of systems biology.