The performance of our method when using the TFBS data with different qualities. To check the robustness of our method against different TFBS qualities, we tested four different posterior probability thresholds (0.2, 0.3, 0.4 and 0.5). The figure shows that no matter which threshold is used, the performance of our method is always the same (i.e. superior to 10 out of 11 existing methods) on the performance index 1. This suggests that our method is robust against different thresholds of posterior probability to control the TFBS quality.