Figure 2

Representative images of metaphase spreads hybridized with telomeric PNA probes using Q-FISH (panels a-d) and CO-FISH (panels e-h) protocols. (b-d) Aberrant telomeric structures (blue arrows indicate long strings of fragmented telomeric signals: indicative of fragile telomeres) (e-h) The majority of chromosomes within a metaphase spread showed characteristic CO-FISH hybridization patterns in which telomere signals at opposite ends of the chromosome were in the trans position with respect to the sister chromatids. (a,e and f) Chromatid breakages in metaphase events of FANCD2 cells (arrows indicate no telomeric signals on the breakage points). (g-h) Telomere sister chromatid exchanges (red arrows).