Modelling chromosomal aberration induction by ionising radiation: the influence of interphase chromosome architecture.

Several advances have been achieved in the knowledge of nuclear architecture and functions during the
last decade, thus allowing the identification of interphase chromosome territories and sub-chromosomal
domains (e.g. arm and band domains). This is an important step in the study of radiation-induced
chromosome aberrations; indeed, the coupling between track-structure simulations and reliable
descriptions of the geometrical properties of the target is one of the main tasks in modelling aberration
induction by radiation, since it allows one to clarify the role of the initial positioning of two DNA lesions
in determining their interaction probability. In the present paper, the main recent findings on nuclear and
chromosomal architecture are summarised. A few examples of models based on different descriptions of
interphase chromosome organisation (random-walk models, domain models and static models) are
presented, focussing on how the approach adopted in modelling the target nuclei and chromosomes can
influence the simulation of chromosomal aberration yields. Each model is discussed by taking into
account available experimental data on chromosome aberration induction and/or interphase chromatin
organisation. Preliminary results from a mechanistic model based on a coupling between radiation trackstructure
features and explicitly-modelled, non-overlapping chromosome territories are presented.