Fig. 8.

Quantitative measures of map properties for joint development of ORI and OD maps using correlation functions as in Figure7, except that we now also allow the width of C^OD to vary, proportional to the parameter γ (indicated by symbols). The growth rate ratio λ₀^OD/λ₀^ORI+ is varied by varying d. a, Solid curves, 〈m〉, the degree of OD segregation (see Eq. 11); dotted curves, Z, the degree of RF segregation of ON and OFF subregions (Eq. 12). b, Mean ORI selectivity, Q (Eq. 13). Higher values of λ₀^OD/λ₀^ORI+ favor development of OD, whereas lower values favor ON/OFF segregation and development of ORI selectivity. In all cases, ORI selectivities and maps are matched in the two eyes (because λ₀^ORI− = C^ORI− = 0; see Fig. 6f). c, The range of ratios λ₀^OD/λ₀^ORI+ that allows co-development of OD and ORI selectivity grows wider with increasing width, γ, of C^OD. We define the lower bound on the range of ratios as the value at which OD segregation 〈m〉 > 0.5 (from a) and the upper bound as the value at which ORI selectivity Q (from b) falls below the value it would have for λ₀^OD/λ₀^ORI+ = 0, i.e., for development with C^OD = 0. The growth rates (computed numerically) are given by: λ₀^OD = 14.04 d, 12.46d, 9.74d, 7.62d, and 3.94d for γ = 2.5, 3, 4, 5, and 8, respectively; λ₀^ORI+ = 12.84.