Figure 2.

An inhibitor dilution model can yield robust adder behavior in asymmetrically dividing, budding daughter cells for biologically relevant parameter values and is consistent with experimental observations of adder behavior. Simulations were performed assuming noisy integrator synthesis and noisy asymmetry growth (section 3.1). (A,B) Colored hexes denote heatmaps of volume at birth and division for daughter cells only, overlaid with a linear regression fit and red V_d values, averaged over data points binned with respect to V_b. Noise values are: (A) σ_x/〈x〉 = 0.0, ${\sigma }_{\Delta }/\langle \tilde{\Delta }\rangle =0.05$, ${\sigma }_s/\langle \tilde{\Delta }\rangle =0.05$; (B) σ_x/〈x〉 = 0.0, ${\sigma }_{\Delta }/\langle \tilde{\Delta }\rangle =0.05$, ${\sigma }_s/\langle \tilde{\Delta }\rangle =0.05$. (C–F) Heat maps of linear regression slopes from fitting V_b vs. V_d for daughter cells only. Variation is with respect to ${\sigma }_{\Delta }/\langle \tilde{\Delta }\rangle$ and σ_x/〈x〉. ${\sigma }_s/\langle \tilde{\Delta }\rangle$ and 〈x〉 are as labeled. Black outlines provide a guide to the eye for regions in which adder-like behavior is observed (slope = 1.0 ± 0.1).