Average growth rate effects of gene deletions. The average growth rate of strains containing no deletions (open bars), single deletions (shaded bars), and two deletions (solid bars) with 95% confidence limits are shown. Five environments were used: YPD (rich medium), heat (YPD and 37°), SD (minimal synthetic medium), caffeine (8 mm caffeine in YPD), and saline (1 m NaCl in YPD). (A) MGR. (B) RGR.