Figure 2

Distribution of absolute number of samples in which duplicated gene pairs expressed. (a) block, (b) dispersed, and (c) tandem pairs. Each cell corresponds to a range of absolute number of samples. The top-right cell represents both members of gene pairs expressed in 13–15 samples; the bottom-left cell represents both members expressed in 1–3 samples; the bottom-right cell represents gene 1 expressed in 13–15 samples and gene 2 expressed in 1–3 samples. Gray scales indicate the number of duplicated pairs within the corresponding squares. Since two members of duplicated pairs are unordered, we set the expression number of gene 1 less than that of gene 2 for each duplicated pair.