Chromosome or chromatin condensation leads to meiosis or apoptosis in stationary yeast (Saccharomyces cerevisiae) cells.

When starved of essential nutrients, yeast cells cease mitotic division and enter an alternative state called the 'stationary phase'. In this paper, we report that stationary cells enter two major pathways: meiosis and apoptosis. Using transmission electron microscopy, five types of cell were identified in the stationary phase: (1) cells with chromosome condensed nuclei; (2) cells with normal, homogeneously stained nuclei; (3) sporulated cells; (4) apoptotic cells, in which chromatin, but not individual chromosomes, was condensed; and (5) dead cells, in which nuclei and cytoplasm were degraded. Further evidence using live cell imaging and mutation analysis suggested that cells with condensed chromosomes underwent meiosis, whereas chromatin condensed cells underwent apoptotic cell death. Cells with homogeneous nuclei are believed to be in the true resting state and undergo cell death when starvation continues. Chromosome or chromatin condensation may serve as a hallmark of life or death for stationary cells.