Individual gene expression across conditions variably correlates with growth rate in the full E. coli RNA data set. The Growth Correlation Index (GCI) measures the correlation between growth rate and expression for individual genes. The top row shows the two genes with the most negative (A) and most positive (B) GCI values across all conditions (⁠$GCI=−0.76$ and $GCI=0.72$⁠, respectively). (C) The distribution of GCI values for all genes (left-skewed) against a reference data set with permuted expression and growth data (centered).