Figure 2

Genome-wide scans. Histograms of MFEs for a sliding window of 200 bases calculated by scanning the largest chromosomes of six species. The histograms for the native direction (blue line) and the reverse direction (dashed red line) show a small but clear offset towards lower MFEs (in Kcal/mol units) in the native direction. In contract, the complementary sequence (green line) is almost indistinguishable from the native direction (blue line). The X axis in all six histograms represents the MFE (set to range between -60 to -10), and the Y axis is the number of sliding windows that yielded the respective MFE value.