Figure 7

Topographic maps in heterozygous EphA3 ki/+ knockins in the conditions of reduced overall levels of EphA receptor in the retina. As the levels of receptor expression are reduced progressively from (A and B) EphA4+/+, to (C and D) EphA4+/-, and (E and F) EphA4-/-, the position of bifurcation (dashed line) shifts in the temporal direction in our simulations. The reason for this behavior is the desaturation of EphA receptor signaling leading to the increased impact of additional EphA3 receptor in EphA4 mutants. The levels of receptor are shown on the left in each case, with different forms of receptor indicated.