Biophysical analysis of radiation induced initial DNA fragmentation.

Production of double strand breaks (DSBs) and double-stranded DNA fragments after irradiation with high energy nitrogen ions was simulated with stochastic track generation and a high-order chromatin structure (HOCS) model representing a segment of interphase chromosome. The non-random distribution of DNA fragments is predicted for irradiation of HOCS. Agreement with the experimental data is obtained. The influence of HOCS and the role of the background component in DNA fragment distributions are discussed.