A Model fitting to the experimental tFT-Bcd ratio in early n.c. 14 as function of AP position for the different models Black line represents mean measured ratio of tFT-Bcd reporter with mCherry-sfGFP-Bcd in y/w flies. The shadowed area represents ±1s.d. Inset is same as main panel, except for the tFT-sfGFP-fmCherry-Bcd reporter. 