A mathematical model of DNA fragmentation induced by gamma-rays

Abstract:- A suitable modelling of the radiation- nduced DNA fragmentation may greatly help in developing a clearer biophysical description of radiation action in mammalian cells. We have developed a model aimed at describing the DNA fragment distribution induced by ionising radiation. It is based on a random fragmentation formalism already developed in the literature, generalized in such a way to be applied to any initial size distribution. This model has been applied to the DNA breakage induced in mammalian V79 cells by 25 Gy g-rays, as determined by the pulsed-field gel electrophoresis technique in the size range 23 kbp – 5.7 Mbp. The usual random breakage model, based on the assumption of initial monodisperse population of molecules, strongly disagrees with the experimental results, while our model gives a quite good description of the observed pattern when the experimental distribution in the non-irradiated sample is taken as the initial distribution in the model. Key-Words:- DNA, radiation-i duced damage, fragmentation, double-strand breaks, pulsed field gel electrophoresis, ionising radiation, g-rays V79 cell