Graphical representation of the parameters used to detect genes with nutrient and growth-rate effects. An overall mean expression level (grey dotted line) and linear regression (black dashed line shown only for nitrogen limitation) is calculated across all four conditions. Separate means and linear regressions are then made for each condition (C, N, P and S) separately and compared. In this example we highlight significant nutrient effects (of opposite signs) in carbon (a) and phosphate (b) limitations, significant growth-rate effects in carbon (c) and sulphur (e) limitations (the slopes are significantly different from 0) and nutrient-specific growth-rate effects in nitrogen (d) limitation (slope is significantly different from overall slope).
Gutteridge et al. BMC Biology 2010 8:68 doi:10.1186/1741-7007-8-68