ebi-1 causes the circadian clock to oscillate with a short period. (a,b) Transgenic seedlings carrying the LUC reporter gene fused to the CAB2 promoter were entrained under 12-h light/12-h dark cycles for 7 days, after which luminescence was monitored in either constant darkness (a) or constant red light (measured in counts/second, CPS) (b): WT, open squares; ebi-1, closed squares. The plots are representative of multiple experiments and are an average of between 24 and 79 individual seedlings; error bars are standard error of the mean. The inset in (b) is a mathematical analysis of the experiment represented in (b): period estimates for individual seedlings plotted against their relative amplitude errors (R.A.E.). (c) Representative leaf movement plots for WT (open squares) and ebi-1 (closed squares).