DNA repair after irradiation, visualized by optical mapping. DNA samples were extracted at different time points from D. radiodurans R1 (wild type) cells. The irradiation and recovery conditions (time interval after irradiation) for each image were: (A) 0 Gy, 0 hours; (B) 17.5 Gy, 0 hours; (C) 17.5 Gy, 2 hours; (D) 17.5 Gy, 4 hours; (E) 17.5 Gy, 6 hours; (F) 17.5 Gy, 16 hours; (G) 17.5 Gy, 24 hours. Scale bar, 20 µm. reprinted from Lin et al.