Parameters for peak detection. (A) Graph is a distribution profile of CACGTG in Arabidopsis promoters. Average with 15 bin is shown. The dotted line indicates the Base Line, which is an average of -1,000 to -500. The light grey area shows Peak Area. The dark grey area is Δarea, an indication of the fluctuation from the Base Line from -1,000 to -500. In addition, the following parameters have been defined: Relative Peak Area (RPA) = Peak Area/total area; Relative Peak Height (RPH) = peak height/Base Line; Peak Area/basal fluctuation = Peak Area/Δarea per peak width; Peak height/SD = peak height/standard deviation of occurrence from -1000 to -500. Several parameters of this graph are shown in Table 2 (CACGTG). (B) All the hexamers were analyzed to obtain various parameters, and (Peak Area/basal fluctuation) and peak position were calculated. The graph shows the results. Each dot shows the data of an individual hexamer. Among the 4,096 hexamers (grey dots), 247 peak positive hexamers have been selected (solid dots). The graph demonstrates that hexamers with a significant value have a peak position from -200 to -13 (the most downstream position after smoothing).