Mechanisms of DNA double-strand break repair and their potential to inducechromosomal aberrations

DNA double-strand breaks (DSB) are considered to be critical primary lesion s in the formation of chromosomal aberrations. DSB may be induced by exogen ous agents, such as ionizing radiation, but also occur spontaneously during cellular processes at quite significant frequencies. To repair this potent ially lethal damage, eukaryotic cells have evolved a variety of repair path ways related to homologous and illegitimate recombination, also called non- homologous DNA end joining, which may induce small scale mutations and chro mosomal aberrations. In this paper we review the major cellular sources of spontaneous DSB and the different homologous and illegitimate recombination repair pathways, with particular focus on their potential to induce chromo somal aberrations.