A yeast strain has the genotype ADE2ade2 TRP2trp2 ura3ura3 F

A yeast strain has the genotype ADE2/ade2 TRP2/trp2 ura3/ura3. Following sporulation and plating, you observe 160 colonies growing on YPD. If you replica plate these colonies onto SC –ade –trp plates, how many colonies would you expect to grow?

Solution

80 colonies are expected to grow on the -ade and -trp plates because only the strains that do not require -ade and -trp for growth will grow and the other will not grow as they require -ade and -trp for growth in the minimal medium.