Figure 3. Five NP patterns characterized by frequency domain.

Shape characteristics of five NP patterns were visualized by scalogram representation of wavelet coefficients. Each scalogram was labelled by PC name and the sign (vertical orientation) is shown in the wave shapes at the top of each box. The x-axis indicates the relative position ranges from −500 to +500 bp from a cis-regulatory element, and y-axis is the scale of a pseudo frequency of Morlet wavelet, ranging from 64-1024 Hz. The intensity of the real part of the wavelet coefficient is coloured from blue (negative) to red (positive), as shown in the colour-bar in bottom-right. The right box indicates the total power (x-axis) spectrum at each frequency (y-axis) of each PC in the window. The peak in the spectrum represents the major periodic component.