TUNEL assay.

<p>Epifluorescence photomicrography of embryos at 48 and 90 hpi classified according to the speed of development as either Fast (reached the fourth cell cycle at 48 hpi) or Slow/4 cells (exactly 4 cells and prior to the fourth cell cycle at 48 hpi). A) Fast embryo at 48 h of culture; B) Slow/4 cell embryo at 48 h of culture; C) embryo at 48 h of culture submitted to DNA fragmentation via exposure to DNase (technique positive control); D) Fast embryo at 90 h of culture; E) Slow/4 cell embryo at 90 h of culture; and F) embryo at 90 h of culture submitted to DNA fragmentation via exposure to DNase. The blue fluorescent nuclei indicate total cell number and red fluorescent staining indicates cells with fragmented DNA.