With the completion of the Arabidopsis genome sequencing, it is tempting to apply reverse genetics approaches to the myriad of conspicuous gene duplications. While this will likely to continue to be a fruitful approach in elucidating gene function, we believe that many cases of genetic redundancy will be missed focusing solely on this approach. We describe here the story of CRABS CLAW (CRC), studies of which have revealed several instances of genetic redundancy. While some of the cases of genetic redundancy that we identified represent biochemical redundancy due to duplicate genes, most instances do not reflect a biochemical redundancy, but rather are the result of complex genetic interactions between genes directing the development of the carpel. We argue that this latter class is difficult to predict a priori, and is thus not amenable to standard reverse genetic approaches. In addition, we note some aspects of mutagenesis that we have found particularly instructive.