Fig. 3.

Competitive effect between adjacent pigment cells. (A) Schematic drawing of the experiment to measure the short-range effect of xanthophores on melanophore. In a 20 dpf-fish, melanophores are dispersed in the middle region where xanthophores become dominant soon after. Xanthophores adjacently surrounding each melanophore were ablated, and the survival of these cells was tracked. (B, C, and D) Survival of the melanophores in relation to the adjacent cells. In the control region, no ablations were made, and the dispersed melanophores were surrounded by xanthophores (B, right square) the number of the melanophore decreased (day 6) and disappeared at day 9. In the left square region, the xanthophores adjacently surrounding the melanophores were ablated.(B, right square) A half of melanophores survived at day 6. (E and F) Time course of melanophore survival after ablation. Survival ratio is shown as the relative value against the original number. Total number of the tested melanophores was 50 for each graph. Black bar, melanophores remained alive in the yellow stripe region; yellow bar, melanophores migrated into the black stripe region; white bar, melanophores disappeared (dead). (G) Schematic drawing of the experiment to measure the short range effect of melanophores on xanthophores. Melanophores in the black stripe region were continuously ablated to enhance the survival of melanophores in the middle region. (see Figs. 1 and 2). (H, I, and J) Survival of the pigment cells at days 3, 6, and 9 after ablation of black stripes. The region in the left square is filled with xanthophores. As the time passed, all of the xanthophores in the left region accumulated the fluorescent pigment and looked very healthy. The right square region is occupied by the mixture of melanophores and xanthophores, at day 3. As the time passed, melanophores became dominant, and the xanthophores disappeared. This should be caused by the adjacent melanophores because the xanthophore in the left region stayed alive in the same period. (K–P) Magnified picture of the outlined area in H–J.