(C) Fusion triggers fission. Cumulative probability of the occurrence of fission events at different intervals after fusion events occur (fraction of all fission events occurring after the given time interval). The data are fit to a hyperbolic function representing linkage between the two events (INS1, R2=0.98; COS7, R2=0.96). The straight line shows the predicted linear growth rate in fission event probability over time that would be expected if the fission had occurred independently from the fusion events (dashed lines INS1, R2=0.77; COS7, R2=0.84; see Supplementary data). 