Inverse symmetry indexes for codons and 3-mers.

Inverse symmetry indexes computed from counting codons in genes () and from counting 3-mers in gene-concatenates () for four type-representative chromosomes. The four typical bacterial genomes are: A, C. acetobutylicum; B, E. carotovora; C, Y. pestis: and D, Synechocystis. Given a segment - Whole, Lead or Lag - the number of codons is counted in all gene-embedding sequences in the segment, and the number of 3-mers is counted in the gene-concatenate formed by stitching together all gene-embedding sequences (Methods). In the last three columns listing , “W” means gene-embedding sequences are spliced from the entire chromosome, “Ld”, from the ori to ter strand, and “Lg”, from the ter to ori strand. Codons do not exhibit inverse symmetry (()) in all cases. 3-mers exhibit strong inverse symmetry (()) in “W” always, and in “Ld” and “Lg” according to type.