Fig 4.

Classification of TFRs based on the orientation and proximity of adjacent genes. (A) Type I TFRs are transcribed divergently from an adjacent gene. A regulatory relationship is predicted when this intergenic region is less than 200 bp. (B) Type II TFRs are predicted to be cotranscribed with and to regulate an adjacent gene based on a distance of less than 35 bp between genes. (C) Type III TFRs show neither of the above-described relationships with adjacent genes, and a regulatory relationship with the adjacent genes cannot be predicted.