Fig. 5

Microscopic analysis and apoptosis assay in a representative Stage 22 unisexual Ambystoma embryo. a and d Hoechst stain (blue fluorescence) indicates locations of cell nuclei. b Unisexual positive control, treated with TACS-NucleaseTM (Trevigen), a proprietary endonuclease, exhibits positive TUNEL staining as is evident by green fluorescence indicating the presence of DNA damage. e Experimental unisexual sample exhibits negative TUNEL staining (no green fluorescence), indicating absence of DNA damage characteristic of apoptosis. c and f Hoechst stain and TUNEL labeling merged with phase contrast microscopy