Fission yeast is a popular model organism for the study of the cell cycle. It grows quickly compared with other eukaryotic species; under normal conditions, a wild-type cell takes about 2.5–3 h to complete a cell cycle. A wild-typeS. pombecell has a rod shape, grows by elongation, and divides by medial fission. These characteristics allow the position of a cell in the cell cycle to be estimated simply by visualization of cell morphology. The organization of the fission yeast cell cycle is similar to that in larger cells. Because fission yeast has only three chromosomes, it is also a convenient organism for the cytological study of chromosome dynamics. Thus, fission yeast has become a popular system for studies of cell growth and division (1 –4 ).
