Hamburger Hamilton stage 13 chick embryo was electroporated with constructs encoding Sfrp-2 (marked by expression of nuclear GFP) and Wnt-3a (marked by expression of membrane bound GFP) and then incubated until stage 21. A transverse section was then immunostained for Pax-7 (blue) and antiphosphohistone H3 (red). The upper left panel shows the original image, while the other three panels show digitally manipulated versions of the original image. See Galli et al., Developmental Dynamics 235:681–690. © 2006 Wiley-Liss, Inc.