Chromosomal rearrangements in Arabidopsis mutants revealed by repeated FISH

The stability of plant nuclear genome is a necessary condition for the faithful transmission of genetic information through cell lineages. When DNA damage occurs due to various impairments, cells start a number of repair processes including ligation of broken chromosomes. As a result, dicentric chromosomes can be formed. Dicentrics are easily detectable as anaphase bridges during following mitosis. Using Arabidopsis as a model plant, we developed a sensitive cytogenetic assay to identify specific chromosomal rearrangements. Here we show Arabidopsis tert-/- and atm-/- mutants and their chromosome rearrangements and fusions analysed by fluorescence in situ hybridization (FISH). The method is based on successive rounds of FISH with chromosome-specific probes and the comparison of resulting FISH images.