You have a diploid yeast strain of unknown genotype You spor

You have a diploid yeast strain of unknown genotype. You sporulate the diploid and plate equal numbers of spores onto YPD or synthetic media. You collect the following data:

100 colonies on YPD

100 colonies on SC –tryptophan

50 colonies on SC –adenine

50 colonies SC –uracil

0 colonies on minimal media

What are possible genotypes of the diploid? Select all that apply.

Homozygous mutant for ADE2.

Heterozygous for URA3.

Homozygous wildtype for TRP2.

Solution

The diploid yeast strain of unknown genotype, when sporulated and the equal numbers of spores are plated onto YPD or synthetic media. we get:

100 colonies on YPD

100 colonies on SC –tryptophan

50 colonies on SC –adenine

50 colonies SC –uracil

0 colonies on minimal media

The possible genotypes are:

Heterozygous for URA3

and

Homozygous for TRP2