DNA as the genetic material is a topic of intense interest in the 21st century, with the genomes of many organisms having been sequenced. The double ... Show synopsis DNA as the genetic material is a topic of intense interest in the 21st century, with the genomes of many organisms having been sequenced. The double helix structure discovered by Watson and Crick 50 years ago is now very familiar and its importance for DNA function is widely appreciated. structure that have important biological consequences. knotting, and catenation (linking). Unfortunately, a full understanding of these features of DNA structure requires the grasp of concepts that can prove difficult for both students and more advanced researchers. wider appreciation of DNA topology. DNA Topology starts with a basic account of DNA structure before going on to cover DNA supercoiling, the definitions and physical meanings of linking number, twist, and writhe, and the free energy associated with supercoiling. curved surface and its application to the nucleosome, followed by the phenomena of DNA knotting and catenation. topology, and, most importantly, with the biological significance of the topological aspects of DNA structure. accessible way, drawing on interesting and relevant examples.