Figure 2.

Expected patterns of meiotic segregation in a yeast strain heterozygous for a mutant insertion in HIS4. We show the chromatids as double-stranded DNA molecules with sister chromatids held together at the centromeres (shown by the ovals). The HIS4 genes are depicted as long rectangles; the mutant insertion is shown as a black marking. His⁺ spore colonies are shown as white circles, and His⁻ spore colonies are shown as black circles.