File:Fpls-02-00008-g003.png

English: Metaphase chromosomes of the field bean. (A) Chromatid-type aberrations after bleomycin treatment. Left cell: isochromatid break (arrow head), the centric, and the acentric chromatid fragments are surrounded by black dots, the homologous undamaged chromosome is surrounded by white dots. Middle cell: symmetric reciprocal chromatid translocation (arrow) and two terminal chromatid breaks (arrow heads). The latter with the broken fragment either switched to the opposite site of the undamaged sister chromatid (left) or being at least 90° apart from the other break-end as in case of the broken secondary constriction (right). Right cell: interstitial deletion (arrow), the deleted fragment remains attached to the undamaged sister chromatid, the chromosome involved is surrounded by black dots. (B) Interstitial asymmetric chromatid labeling (arrows) after bleomycin treatment in the presence of EdU during S phase. (C) Interstitial asymmetric chromatid labeling (arrows) after bleomycin treatment in the presence of EdU during G2. The asymmetric signals appear on chromosomes II, IV, V, and VI, respectively, at interstitial heterochromatic regions composed of homologous tandem repeats (Fuchs et al., 1994).