Rejoining pathways underlying intrachange formation depend on interphase chromosome structure

: Fluorescence in situ hybridization technique with dual-arm painting of the same chromosome allows to study radiation induced intrachromosomal exchange aberrations (intrachanges). The formal method for analysis of FISH data developed by Savage and Simpson includes an arrangement of chromosomal reactive breaks on chromosomes and chromosome arms (CAB system). That method predicts types and frequencies of aberrations assuming random restitution/rejoining of breaks free ends. However experimental data suggest that many aberrations are formed non-uniformly along the chromosomes and chromosome arms. In the present paper the system for classifying rejoining pathways underlying intrachange formation is proposed which does not require random restitution/rejoining suggestion. It takes into account the parameters of interphase chromosome structure. Types and frequencies of intrachanges are considered by exploring different hypotheses about exchange initiating chromosomal lesions.