Fig. 10. Male embryo at gastrulation with serosa cells covering the whole embryo length. Serosa cells show a well-formed chromocenter labeled by the HP-1 antibody. DAPI staining (left), merged images (right), with DAPI fluorescence in red and HP-1 immunolabeling in green. HP-1 immunolabeling is not apparent over the chromocenters of all embryo nuclei, because the immunofluorescent signals are scattered over many focal planes. Scale bar: 10 µm.