Entropy and mutual information in physiologic RSS. (a) Position-wise entropy H
at each position in an alignment of physiologic 12-RSS (upper bar) and an alignment of physiologic 23-RSS (lower bar). Position in the alignment is shown above each bar, and the value of H
at position i is indicated by the color of the bar at that position. (b) Mutual information (MIi,i') between pairs of positions in physiologic 12- and 23-RSS. MIi,i' values between positions in the 12-RSS are shown in the upper panel, and MIi,i' values between positions in the 23-RSS are shown in the lower panel. Location in the alignment is given on the x- and y-axes. The black lines mark the heptamer (H)-spacer (S) and spacer-nonamer (N) boundaries. The color at the intersection of an x-axis and a y-axis grid linegives the MI contained in the positions corresponding to the two grid lines. The actual MI computed from the RSS alignments are shown in the left panels, and one of 300 permutations is shown on the right as an example of the level of MI observable between each pair of positions in the absence of any correlation between them.