Fig. 3. DiI filled gata::GFP-positive vrc cluster where first GFP axon has just started to grow to midline shows no red axons ahead of the GFP. gata::GFP embryo fixed immediately after the first GFP-positive axon began growing to midline and the vrc cluster (asterisk) was filled with DiI to label axons from the vrc. (A) Front view of the green channel showing the GFP-positive vrc cells and the first GFP-expressing growth cone (arrow) projecting towards the midline. (B) Merged green and red emission channels showing the injected vrc cluster (asterisks) and the labeled growth cone (arrow). No other DiI filled axons are visible ahead of the GFP-expressing axon. (C) Red channel showing the DiI fill and the labeled DiI growth cone (arrow). Scale bar: 10 µm.