Figure 2.—

Genetic screen for yeast mutants with defects in chromosome segregation. To monitor chromosome loss, a yeast strain containing a YAC was used. The strain is mutant for trp1, ura3, and ade2 genes and contains a YAC with selectable markers TRP1, URA3, and ADE2. The YAC also contains a centromere, origin of replication, and telomeres. Cells are spread on agar plates, exposed to UV light, and allowed to form colonies. A visual screen for red-sectored colonies is used to isolate mutants with increased YAC loss.