The majority of the genes in the three states, fed, fasted and sibutramine-treated, were similarly affected by the diurnal signal. Correlations to PER1 in the three states were very high (blue dots), indicating that the diurnal effect overwhelmed the rest of the perturbations. However, a small number of genes had correlations to PER1 that were significantly different between the states (green dots). The correlation plots are slightly tilted off the diagonal.
Loboda et al. BMC Medical Genomics 2009 2:7 doi:10.1186/1755-8794-2-7