Residuals of the Operon Model Regressions Used to Estimate Expression (Without Intercept), Showing Unexplained Variation

<p>Only residuals with absolute values larger than 10⁻¹⁴ are shown. Thus, variation in all but nine of the 44 operons is completely explained. All operons containing tDNAs with these non-zero residuals are arrayed at the bottom, showing true tDNA order from 5′ to 3′. All such tDNAs are in single-copy except for the genes encoding Ala1B in the ribosomal operons, indicated by vertical stacking at the bottom, Arg3<i>,</i> which is repeated three times in the <i>serV</i> operon, and MetM<i>,</i> Gln1<i>,</i> and Gln2<i>,</i> which are each repeated twice in the <i>metT</i> operon (for its true configuration, see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.0010012#pcbi-0010012-t001" target="_blank">Table 1</a>). Residuals are shown in μM units, those of standardized concentrations. Residuals are shown for each tDNA in order of increasing growth rate from 0.4 (leftmost) to 2.5 doublings/h (rightmost). Positive (negative) residuals indicate underestimation (overestimation) by the model.