Fig. 9. An advanced stage of blastoderm formation in a male embryo (512-1024 nuclei stage). Serosa cells forming a cap over the anterior pole. In all panels, DAPI staining alone is on the left and merged image on the right, with DAPI in red and HP-1 immunolabeling in green. (A) Higher magnification of embryo nuclei displaying a bright DAPI-stained chromocenter labeled by the HP-1 antibody. (B) Most of the serosa nuclei show immunolabeling over a differentiated mass of chromatin (arrows) not yet showing the characteristic bright DAPI staining of the chromocenter. Scale bars: 10 µm.