Coverage of the COX I gene. The coverage of the COX I gene (position 5270 to 6824). The division into groups, A, B, and C (not shown) of different libraries were performed by clustering on coverage of the different parts of the gene. (A) A subset of libraries from group A having the characteristic dip in expression level in the range approximately from position 5800 to 6000. (B) A subset of group B libraries having a general lack of expression within the region ranging from position 5270 to approximately 5900. The full plots for all groups are shown in [additional file 1], and plots for individual libraries can be found in [additional file 3].