Analysis of telomere maintenance in various cell lines. A. Frequencies of T-SCEs (event/metaphase) in 5 cell lines. A minimum of 30 metaphases/cell line were analyzed in two independent experiments. B. Examples of T-SCEs in a metaphase cell from the EUFA423 cell line. Some of T-SCEs are indicated by arrows. C. Telomere length analysis by Q-FISH. TFI - telomere fluorescence intensity (arbitrary units). PD - population doubling. D. Frequencies of chromosome fusions. Error bars represent SEM in A and D and SD in C.