A map, obtained through electron microscopy using the Kleinschmidt spreading technique (q.v.), of a DNA molecule that shows the positions of denaturation loops. These are induced by heating the molecules to a temperature where segments held together by A=T bonds detach while those regions held together by G[tbond]C base pairs remain double-stranded. Formaldehyde reacts irreversibly with bases that are not hydrogen bonded to prevent reannealing. Thus, after the addition of formaldehyde the DNA molecule retains its denaturation loops when cooled. Denaturation maps provide a unique way to distinguish different DNA molecules.
Subjects: Genetics and Genomics.