Figure 4.

Flow cytometry histograms of synchronised HeLa S3 cells. From left to right the histograms correspond to 7.5, 9, 10.5, 11.5 and 13 h after release of the second thymidine block. Categories 3 and 4 have been irradiated with a dose of 3 Gy in late S/early G₂ phase.