Robustness of the gap-gene expression boundaries to variations in the <i>bcd</i> gene dosage.

<p>(<b>A</b>) Time- and circumference-averaged Hb (, solid lines) and Kni (, dashed lines) total copy-nymber profiles along the AP axis for various <i>bcd</i> gene dosage factors and . Inset: the average occupancy of the promoter states with five bound morphogen molecules as a function of . (<b>B</b>) Comparison of the boundary position as a function of for to values measured by Houchmanzadeh et al. <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002654#pcbi.1002654-Houchmandzadeh1" target="_blank">[5]</a> (black line). The red line shows the simulation results for the system without mutual repression. Note the good agreement between the experimental data and the simulation data of the system with mutual repression. (<b>C</b>) Profiles of the average standard deviation of the total Hb (, solid lines) and Kni (, dashed lines) copy number. Inset: as a function of . The grey dashed line represents the Poissonian limit. (<b>D</b>) The Hb boundary width as a function of and , the separation between the Hb and Kni boundaries in a system without mutual repression, for the system with (green) and without (red) mutual repression. is varied by multiplying the Bcd level by .