A rapid screen for chromosome missegregation mutants by DAPI staining

1. Make fresh patches (a nickel coin size) on solid media.
2. Replicate plate on plates which allow your mutants to show phenotypes.
3. Incubate several hours to overnight (depending on your experiment)
4. Scrape off cells on the plates by toothpicks and resuspend in 50 ml of 3.7% formaldehyde/50mM Tris-Cl (pH 7.5) in wells of a 96 well microtiter plate.
5. Let sit for 1 hour at room temperature
6. Discard solution by turning upside down
7. Put water in the wells using a squashing bottle gently.
8. Discard water as in step 6.
9. Repeat steps 7 and 8 again.
10. Put 50 ml of 50mM Tris-Cl (pH 7.5) containing 100 ng/ml DAPI (samples can be kept at 4^oC for several weeks).
11. Put the top on and seal by a parafilm.
12. Turn upside down, put on the stage and examine using a lens for long distance focus.