Folders: 1. Pictures: contains graphs of ΔG of DNA/DNA and RNA/DNA duplexes for the whole chromosomes of S.cerevisiae 2. Databases: contains Access databases used for calculation of ΔGmin and ΔGavg of DNA/DNA and RNA/DNA duplexes 3. Perl software : the program used for calculation of ΔG of DNA/DNA and RNA/DNA duplexes 4. S2PS: Perl software drawing graphs(see Folder "Pictures") of ΔG of DNA/DNA and RNA/DNA duplexes for the whole chromosomes 5. Supplementary tables: contains Tables S1, S2, S5 and S8. Note: The coordinates of all features are presented by their “start” and “end”, where “start” is the smaller position number and “end” is the greater position number of the feature in the Watson DNA sequence (Watson strand runs 5’ to 3’ from left to right and Crick strand runs 3’ to 5’ from left to right). This is required for the proper work of the Databases. Note that these “start” and “end” do not correspond to the real start and end of the features. The coordinates of the real start and end depend on the strand to which the feature belongs to. For the features belonging to Watson strand the “start” and “end” correspond to the real start and end. For the features belonging to Crick strand the “start” and “end” are reversed: the “start” corresponds to the real end and the “end” corresponds to the real “start”.