Figure 1.

Schematic illustration of the process of mating and meiosis in fission yeast. In response to nutritional starvation, haploid cells arrest vegetative growth and initiate mating. Cells of the P and M mating-types communicate each other through mating pheromones and conjugate to form a zygote, which then undergoes meiosis and generates four spores in an ascus if starved conditions are maintained. See the text for more explanation.