TFBS motif hits on human pre-miRs tabulated by motif class, excluding those that are primate specific. TRANSFAC motif classes are shown, tabulating hits upon human pre-miRs excluding primate specific pre-miRs. Hits in the set of pre-miRs are compared to hits observed within the corresponding randomized negative control sets (see figure 3 and Methods). *significant at p < 0.01. **p < 1 × 10-7. ***p < 1 × 10-14.