Position-dependent non-uniform coverage of the reads along the hem operon hemCDXY. The vertical axis is the number of reads covered at the positions. The orange and dark green bars at the button of the graph represent the reverse and forward strands, respectively. Segments with arrows represent genes. The graphs were generated using IGB. To make the expression levels for the four genes comparable in different samples, the same scale (1,200) of the vertical axis is used for all the samples. Although this four-gene operon was consecutively covered by the reads under different cultures and growth phases, there are highly similar patterns of position-dependent non-uniform coverage of the reads along the operon in the samples.