DINUCLEOTIDE RELATIVE ABUNDANCE EXTREMES - A GENOMIC SIGNATURE

Early biochemical experiments establisbed that the set of dinucleotide odds ratios or 'general design' is a remarkably stable property of th e DNA of an organism, which is essestially the same in protein-coding DNA, bulk genomic DNA, and in different renaturation rate asd density gradient fractions of genomic DNA in many organisms. Analysis of curre ntly available genomic sequence data has extended these earlier result s, showing that the general designs of disjoint samples of a genome ar e substantially more similar to each other than to those of sequences from other organisms and that closely related organisms have similar g eneral designs. From this perspective, the set of dinucleotide odds ra tio (relative abundance) values constitute a signature of each DNA gen ome, which can discriminate between sequences from different organisms . Dinucleotide-odds ratio values appear to reflect not only the chemis try of dinucleotide stacking energies asd base-step conformational pre ferences, but also the species-specific-properties of DNA modification replication and repair mechanisms.