Fig. 5

Ploidy cycles can be detrimental when rare, but beneficial when frequent. Population of initially monoploid cells with variable ploidy, P _max  = 6, without reductional divisions (D = 0), was dominated by hexaploids and died out after 440 generations (6-ploid). With 20 % reductional divisions (D = 0.2, 6-ploid_D20%), the same population died out after 290 generations, because the population was dominated by diploids, and diploids are more prone to extinction than hexaploids (see Fig. 1). However, more frequent reductional divisions (D = 0.5, 6-ploid_D50%) rescued the population, because in this case a substantial proportion (35-40 %) of cells in each generation were monoploid. Other parameters as in Fig. 1