Distribution of 10,000 mean R values calculated from randomized genome. Each plot shows the distribution of 10,000 mean R values. Each mean R value is calculated by first randomly permuting the gene order of the genome, and then averaging the R values for every pair of neighboring genes in the resulting gene order. The mean R value in the real genome is shown as a single line on each plot. Both plots are based on the same gene expression dataset: (A) the results on the original dataset (average of mean R = 0.03086, σ = 0.00384); (B) the results after tandem duplicates are removed (average of mean R = 0.03071, σ = 0.00389).