A method for Inversion detection with BrdU. Panel A depicts how a true inversion is formed. Panel B depicts how 2 SCE events can cause a false inversion. Panel C. depicts a 21 chromosome CHO10B2 spread exposed to 2 Gy Fe ion radiation and stain with DAPI (pseudo-colored red) and Anti-BrdU (green). The arrows indicate micro inversions, which are considered true inversions; roughly 1–10 Mb. Panel D. is the black and white image of the Anti-BrdU image used to measure inversions pixel intensity.