Figure 7.

Backstep size distributions. (A–H) Percentage of all backward events in each size class for different MT lattices and in different conditions is shown. Note that y axis is on a log scale. (A–D) Different MT lattices are shown. Probability distributions appear roughly exponential, consistent with backsteps being backslips that have an equal probability of reattachment at each position back along a single PF toward the MT-minus end. (E and F) Under perturbation, this exponential relationship no longer holds. In (E)and (G), longer backsteps appear more probable. In (F) and (H), longer events are very rare.