Mating type switching. (A) Switching of mating types in a fission yeast cell lineage. Cells of type M are marked with red color, blue stands for mating type P. The unswitchable and switchable states are denoted by U and S respectively. The figure has been redrawn from . (B) Trajectories of a simulation run with an inital population of 100 unswitchable cells of mating type P. Cells are dying with a rate constant k
= 0.006 min-1. Mass-doubling time T
= 116 min.