A Chlamydia trachomatic (X axis) vs Chlamydophila pneumoniae (Y axis)

B Escherichia coli (X axis) vs Pseudomonas aeruginosa (Y axis)

Each dot represents a pair of genes with the level of similarity between the encoded proteins sequences indicated by color: red - >1.3 bits/position; blue - from 0.8 to 1.3 bits/position; grey - from 0.3 to 0.3 bits/position; light blue <0.3 bits/position. The similarity scores are expressed in bits/position, rather than in total scores per protein, to remove the bias caused by variation in the protein length.