Fig. 3. Comparison of the boundaries between clones derived from 2-cell blastomeres in zygotes and parthenogenetically activated eggs. (A-D) Individual confocal sections of blastocysts in which the clonal border of the 2-cell stage progeny (yellow dashed line) is tilted with respect to the boundary zone between the embryonic and abembryonic parts (white dashed lines). Blastomeres of fertilised or parthenogenetically activated embryos labelled with different coloured dyes at the 2-cell stage and cultured to the blastocyst stage. The four examples are of the frequently found patterns of clonal distribution in fertilised eggs (A), haploid parthenogenetically activated eggs (B), diploid parthenogenetically activated eggs generated by cytochalasin treatment (C) or electrofusion (D). (E) Series of confocal sections of an individual blastocyst developed from parthenogenetic diploid cytochalasin-treated embryo. The boundary zone is marked with white dashed lines and the border of the blastocoel has been traced on to a central section and is shown projected onto each of the other sections as a red, blue or green dashed line. The clonal border is marked with a yellow dashed line. Panels a-j show individual optical sections at 7.5 µm intervals as a `z-series'. Panels k and l show the dissociated cells of this blastocyst observed by fluorescence or DIC optics respectively. Note that all cells are labelled but not uniformly throughout. (F) Series of confocal sections of the individual blastocyst developed from a fertilised embryo. The boundary zone is marked with red dashed lines and the border of the blastocoel was traced on to a central section and is shown projected onto each of the other sections as a white dashed line. Panels a-h show individual optical sections at 7 µm intervals as a `z-series'. Panels i and j show the dissociated cells of this blastocyst observed by fluorescence or DIC optics respectively. Scale bar: 25 µm (in A for A-D and E for E,F).