Each ascus contains the four spores produced as a result of a single meiosis. Its this characteristic of keeping the meiotic products together that makes baker's yeast a powerful tool in genetics.
Yeast mating mixture showing the characteristic shapes of yeast cells in this step of the life cycle.
|Budding Yeast Cells|
Normally spores form a tetrahedral shape inside the ascus. Occasionally an ascus forms that has all four spores in one plane.