Stanley Joel Korsmeyer (1950-2005) www. sciencemag. org SCIENCE VOL 308 6 MAY 2005 803 the genes uncovered, a skeptic might still judge the screen and its results to have uncertain physiological significance without additional data. In bolstering the case for selected gene candidates, DasGupta and co-workers made a wise choice in exploiting genetic approaches to pursue the notion that some genes uncovered by the screen will have conserved Wnt signaling function in multiple species and models.(Models included reporter gene assays in mammalian cultured cells, development of Drosophila wing imaginal discs, and zebrafish morphogenesis.) Indeed, the authors demonstrate the importance of several new Wnt pathway components—Rab5, the serine-threonine kinase Lats/Warts, and a pairlike homeobox gene (CG4136)—in multiple settings.