Question Set 7 based on this data below BXC genotype HisHis

Question Set 7: based on this data below

BXC genotype: His-/His- Ura+/Ura- Leu-/Ura+ MATa/MATalpha

MATa Tester cell geotype: HIS + URA + ARG- MATa( remeber if yeast grows on MAta tester cells they are MAT alpha )

MATalpha Tester cells genotype: His+ Ura+Leu+Arg-MAtalpha

1. If you have a colony of diploid cells from your YPD colony plate, what will be their histidine genotype? (Recall that any diploid cells on your YPD colony plate originally would have come from a BxC mating.) Can these diploid cells grow on SD? Can these diploid cells mate with either of the mating tester strains?

2. Complete the table below..

Hypothetical haploid colony on YPD plate (colony arose from the sporulation of your BxC diploid

MATa mating tester strain

MATalpha tester strain

Histidine Genotype

Arginine Genotype

Ability of cell to grow on SD

3. Suppose you have a patch of MATalpha haploid cells on your YPD patch plate.   If these cells mate with the cells from the MATa tester cells, what will be the histidine and arginine genotypes of the resulting diploid? Will this new diploid grow on SD.

4. Suppose you have a patch of MATa haploid cells on your YPD patch plate.   If these cells mate with the cells from the MATalpha tester cells, what will be the histidine and arginine genotypes of the resulting diploid? Will this new diploid grow on SD.

5. All of your YPD patches will be replica printed onto a MATa lawn and onto a MATalpha lawn. Each of those replicas will be incubated for 48 hours and then printed onto SD. You will therefore have two SD plates, one originating from the MATa tester replica and one originating from the MATalpha tester replica.  

a. Should any of the specific patches that arise on the SD plate originating from the MATa tester replica also arise on the SD plate originating from the MATalpha tester replica?

b. If you have a diploid patch on your YPD patch plate, will that colony result in growth on the SD plate originating from the MATa tester replica

c. If you have a diploid patch on your YPD patch plate, will that colony result in growth on the SD plate originating from the MATalpha tester replica?

6. Suppose you observe a patch growing on the SD plate originating from the MATa tester replica. What was the mating type of the original colony on the YPD colony plate?

7. Suppose you observe a colony growing on the SD plate originating from the MATalpha tester replica. What was the mating type of the original colony on the YPD colony plate?

Solution

1.colony of yeast cell from original YPD plate will have genotype--His-/His-,Ura+/Ura-,leu-/Ura+(MATa/MAT alpha).These cells will not grow of synthetic defined media(SD) and histidine and uracil metabolism will not take place as the strain is mutant for the mentioned metabolites.Yes, these BxC diploid yeast strains can mate with both MATa amd MAT alpha strains after hapolid spore formation in BxC yeast strain and the strain will grow on both SD and YPD media after amino acid arginine, histidine, leucine supplementation.

2.

no

3)MAT alpha and cross with MATa yeast strain will have genotype as---His/HIS,Ura/URA,Arg-/ARG,/Leu(MATalpha x MAT a). This yeast strain will not grow on synthetic minimal media (SD) but will grow after supplementation with arginine, leucine, histidine and uracil in the minimal media.

4)MATa and cross with MAT alpha yeast strain will have genotype--HIS/His,URA/Ura,ARG/Arg-.Leu (MATa x MAT alpha).No it will not grow on SD media, but will grow after supplementation with arginine,leucine,histidine and uracil in the media.

5)After this, the BxC yeast strain will be crossed with MATa strain and MAT alpha strain, and BXC yeast strain wll be replica plated on both these strains of MATa and MAT alpha and grown on SD plate(without arg,leu,his and ura) and SD+ plate(with arg,leu,his and ura in supplemented media) and incubated for 48 hrs.

a)yes, yeast colonies will arise on both MATa and MAT alpha strain after cross with BXC strain on SD+media but will not grow on SD media plate and both strains BXC and MATa and BXC and MAT alpha tester will grow separately on SD + media plate.

b)If a diploid patch of yeast strain is present on YPD agar, then the BXC yeast strain with MATa tester will grow on SD + plate and not on SD plate alone.

c)If a diploid patch of yeast strain is present on YPD agar, then the BXC yeast strain after cross with MATalpha tester will grow on SD + plate and not on SD plate alone.

6)genotype of cross of BXC and MATa tester yeast strain growing on SD+ plate and not on SD plate will produce 2 strains, strain-1 His-/HIS,Ura+/URA+/leu-/ARG and strain 2--His-/HIS,Ura-/URA+/leu-/ARG. The original mating type after cross will be the same on YPD and SD+ plate and consist of the two strains mentioned.

7)genotype of cross of BXC and MATalpha tester yeast strain growing on SD+ plate and not on SD plate will produce 2 strains, strain-1 His-/His,Ura+/Ura+/leu+/leu-/Arg- and strain 2--His-/HIS,Ura-/Ura+/leu-/Arg-. The original mating type after cross will be the same on YPD and SD+ plate and consist of the two strains mentioned.