Genomic instability of tert/nbs1 manifested as mitotic anaphase bridges. Pistils of experimental plants were treated for microscopy, tissues fixed, squashed and stained with 4',6-diamidino-2-phenylindole (DAPI). (A) Anaphase from G6 wild type plant, (B D) anaphases from double homozygous tert/nbs1, line K12, generation G6 possessing single anaphase bridge, twin bridge and two single bridges, respectively. (E F) Anaphases from single homozygous tert plants, line 69–2, generation G6. Whereas in this tert seed generation, the majority of anaphases exhibited no bridge (E), bridged anaphases were detected in 5.4% (F). (G) The frequency of bridges containing anaphases regardless of number of bridges between the respective anaphases are shown for tert/nbs1, line L2, (blue columns) and tert, line 69–2, (purple columns) in consecutive generations. The numbers of total anaphases scored are indicated in parentheses. No bridged anaphases were detected in nbs1 heterozygotes or wild-type plants. The 95% Confidence Intervals  show significant differences between the values for generations G3 to G6. (ND = due to severe developmental defects, no plants were available for cytology).