Figure 3.

Ectopic EphB1 and Zic2 induce an increase in GFP⁺ fibers in the ipsilateral OT. It is possible that the apparent increase in ipsilateral projections actually arises from a decrease in contralateral projections. To confirm that this is not the case, we divided the GFP⁺ signal in the ipsilateral OT (ipsi OT) by the GFP⁺ area in the retina. If there is not an actual increase in uncrossed fibers, then this ratio should remain constant for all conditions. However, it is clear that there are significantly more GFP⁺ axons in the ipsilateral OT of EphB1 and Zic2 electroporated embryos. n ≥ 10 embryos for each condition, from three or more electroporation experiments. Data represent mean ± SEM. Scale bars, 100 μm. ANOVA: F_(3,68) = 112.10, p < 0.0001; modified t tests: *p ≤ 0.05, ***p < 0.0001.