cleaved double-stranded DNA A DNA molecule which has been cut through both strands at or near the same position - i.e., both phosphodiester backbones are severed - so the molecule is separated into two independent fragments. The ends produced may be blunt (cut at the same position on both strands) or staggered, leaving short single-stranded overhangs ("sticky ends") DS breaks are generally considered to be within 10 bp on each strand as the default clustering distance for scoring DSBs in almost all (ARTRAC, Geant4-DNA/DBSCAN, KURBUC, RITRACKS) models. The range of distances used historically is ~3 to ~30 bp but anything with less than a 10 BP overlap ( effectively one turn) will melt easily, breaking the molecule. Ref: Friedland, W., Schmitt, E., Kundrát, P., Dingfelder, M., Baiocco, G., Barbieri, S. & Ottolenghi, A. (2017). Comprehensive track-structure based evaluation of DNA damage by light ions from radiotherapy-relevant energies down to stopping. Scientific Reports 7, 45161. doi:10.1038/srep45161 double-stranded DNA containing at least one strand break