EXPERIMENTAL FIGURE 19-8 Analysis of DNA content by flow cytometry. Haploid yeast cells were grown in culture and stained with propidium iodide, a fluorescent dye that is incorporated into DNA. The x axis shows DNA content, the y axis the number of cells. The DNA content analysis shows two predominant populations of cells: cells with unreplicated DNA (1C) and with replicated DNA (2C). The cells between the two peaks represent cells that are in the process of undergoing DNA replication.