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Figure S2. No evidence for junctional transfer of LY was detected in sectioned 32-cell stage embryo coinjected with LY and dextran-rhodamine (injection into one dorsal animal blastomere in tier-1). An embryo in which LY appeared to transfer to adjacent cells (A and B) was serially sectioned. ~70 cross sections along the vegetal to animal axis were analyzed and selected sections in this series presented. (C-F) The dyes were unevenly distributed between the injected cell (very bright green or red cell) and a second cell, which is marked by an asterisk. Colocalization of the dyes was always seen, indicating that there was no junctional transfer. (G-H) Cross sections below section no. 38 show no fluorescence, indicating no movement of the dyes into more vegetal cells. Bars: (A) 250 µm; (C) 200 µm.