Yeast

Yeast were plated and each plate was mutagenized by Dr. Loomis by exposing the plate to UV radiation for 9 seconds via a UV light box. Cells that turned red were allowed to grow into larger colonies to be used for the experiment. Four different mutant strains were produced, two of mating type A and two of mating type alpha. Yeast labelled “A” are of the A mating type, while yeast labelled “B” are of the alpha mating type. A YED plate was set up in a grid to perform crosses (Figure 2). Each side consisted of one mating type of non-mutant yeast (HA0/HB0), a known Ade1 mutant (HA1/HB1), a known Ade2 mutant (HA2/HB2), and the two mutant strains for that mating type (MA1/2, MB1/2). After one day of growth, the yeast were crossed gridwise. Two days later, the yeast were replica plated to an MV plate and an MV+Adenine plate (Figure 3). After three additional days of incubation, the yeast colonies were observed. The full procedures followed for all steps can be found on Moodle.