Figure 6. Simulation of MT amplification... | Rockefeller University Press

Figure 6.

$Figure 6. Simulation of MT amplification by severing in WT and spr2-2. (A) Schematic of the model and flow diagram of the relevant events. After crossover creation, the processes of crossover erasure by MT shrinking and severing compete. When severing occurs, the newly created plus end will be immediately rescued and grow with probability Ps,+, the primary amplification event. (B) Time evolution of the fraction of extinction events in WT and spr2-2 as well as the two synthetic mutants, WT(+) spr2-2(−) and spr2-2(+) WT(−). Extinction is more likely in WT than spr2-2, because it is less deep into the unbounded growth regimen. For this reason, spr2-2(+) WT(−) is the least likely to go extinct, coupling a slowly shrinking minus end (less crossover erasure, and hence more amplification) to strongly unbounded plus-end growth (large intrinsic survival probability). (C) Time evolution of the total mean number of MTs starting from a single seed MT (includes the extinction events), showing the stronger amplification of WT compared with spr2-2. Note that the synthetic mutant spr2-2(+) WT(−) outperforms all others because of its low extinction rate coupled to persistent growth.$

Simulation of MT amplification by severing in WT and spr2-2. (A) Schematic of the model and flow diagram of the relevant events. After crossover creation, the processes of crossover erasure by MT shrinking and severing compete. When severing occurs, the newly created plus end will be immediately rescued and grow with probability P_s,₊, the primary amplification event. (B) Time evolution of the fraction of extinction events in WT and spr2-2 as well as the two synthetic mutants, WT(+) spr2-2(−) and spr2-2(+) WT(−). Extinction is more likely in WT than spr2-2, because it is less deep into the unbounded growth regimen. For this reason, spr2-2(+) WT(−) is the least likely to go extinct, coupling a slowly shrinking minus end (less crossover erasure, and hence more amplification) to strongly unbounded plus-end growth (large intrinsic survival probability). (C) Time evolution of the total mean number of MTs starting from a single seed MT (includes the extinction events), showing the stronger amplification of WT compared with spr2-2. Note that the synthetic mutant spr2-2(+) WT(−) outperforms all others because of its low extinction rate coupled to persistent growth.