Figure 2.

Distributions of frequency of intergenic distances between adjacent genes. The upper figures are the distributions of intergenic distances (bp) between adjacent genes at 20 bp intervals in B. subtilis (A) and in E. coli (C), and the bottom figures are their box plots (B and D). The leftmost, rightmost and middle vertical lines of the boxes represent the first and third quartiles and median value, respectively. The intergenic distances more than 1000 bps are not shown. Blue, red and green lines indicate OPs, SOPs and NOPs, respectively.