Fig. 4. Confocal sections of a blastocyst in which the clonal border of the two-cell stage progeny (broken yellow line) is tilted with respect to the boundary zone between the embryonic and abembryonic parts (broken red lines). Blastomeres were labelled with dyes of two different colours at the two-cell stage. The border of the blastocoel was traced on a central section and is shown projected onto each of the other sections as a broken white line. (A-H) Individual optical sections at 7.5 µm intervals in the z-dimension. (I,J) The dissociated cells of this blastocyst observed by DIC optics or fluorescence, respectively. Note that all cells are labelled but not uniformly throughout.