New tool for an old problem: can RNAi efficiently resolve the issue of genetic redundancy?

RNA interference (RNAi) has become a generally accepted tool for inhibiting gene expression in many laboratory organisms. Nagel et al.,(1) in a recent paper, give an example of how this tool can also be used to address the question of genetic redundancy. Their focus was on the redundancy in Drosophila melanogaster of the Enhancer of split gene complex [E(spl)-C] which comprises seven highly related genes. Their somewhat conflicting findings are probably the typical scenario for most RNAi experiments: some expected results and some surprises.