Binding categories differ from the mock background. Ratio (vertical axis) versus the conservation score (horizontal axis) for the set consisting of 75 miRNAs conserved in human, chimp, mouse, rat, dog, chicken. This diagram indicates how each binding category may be differentiated as the conservation score increases (more conserved MREs). It may be seen that 9mers tend to differentiate more than 8mers and 8mers more than 7mers. Except for categories "9mer", "8mer" and "7mer" the remaining categories do not seem to differ significantly from the background.