Fig. 3

Expression of clock genes in fast skeletal muscles during a daily cycle. The values are mean ± SEM (n = 6) of the normalized transcript levels of each clock gene. Significant differences between time points are indicated by different lower-case letters. The line represents the periodic sinusoidal function of gene expression in a circadian cycle constructed from the periodicity parameters calculated using COSINOR. The photoperiod regime is represented by the composite block. White, black and gray, represent the light, dark and light–dark transition phases, respectively