Genes with expression levels that were changed by fasting and feeding were also diurnally regulated. A) In general, genes in the fasting signature were positively correlated with PER1 whereas genes in the feeding signature were negatively correlated with PER1. B) These two heatmaps show the trend of these signatures throughout the day. Morning, afternoon and evenings are separated by yellow dotted lines. The color scale of the heatmaps is the same as in Figure 2A. A solid red arrow depicts PER1 mRNA levels declining over time. C) The proposed phase differences produced by fasting and feeding.