The question is How many different auxotrophic phenotypes

The question is ....

. How many different auxotrophic phenotypes are represented in your collection of three yeast strains?

Suppose you had a fourth yeast strain that was haploid and unable to synthesize the amino acid arginine. If you replica printed it onto the same kinds of plates that you used in this experiment, on which plates would it be able to grow? Explain your answer

Strain

YPD

SD

SD + HIS

SD + LEU

SD + URA

SD + HIS + URA

SD + HIS + LEU

SD + URA + LEU

A

+

+

+

+

+

+

+

+

B

+

-

-

-

-

+

-

-

C

+

-

-

-

-

-

+

-

Strain

Phenotype

Prototroph or Auxotroph

A

Has all amino acids and nutrients needed to synthesize

Prototroph

B

Leu + His and Ura. This strain needs His and Ura to synthesize

Auxotroph

C

Ura + His and Leu. This strain needs His and Leu to synthesize

.

Auxotroph

Strain	YPD	SD	SD + HIS	SD + LEU	SD + URA	SD + HIS + URA	SD + HIS + LEU	SD + URA + LEU
A	+	+	+	+	+	+	+	+
B	+	-	-	-	-	+	-	-
C	+	-	-	-	-	-	+	-

Solution

Three auxotrophic phenotypes are represented in the collection of the three yeast strains.

Strain

YPD

SD

SD + HIS

SD + LEU

SD + URA

SD + HIS + URA

SD + HIS + LEU

SD + URA + LEU

A

+

+

+

+

+

+

+

+

B

+

-

-

-

-

+

-

-

C

+

-

-

-

-

-

+

-

D

In the fourth strain D, which is not able to synthesize the amino acid, arginine can grow only in YPD plate among the above plates because it needs the exogenous supply of arginine for its normal development.

Strain	YPD	SD	SD + HIS	SD + LEU	SD + URA	SD + HIS + URA	SD + HIS + LEU	SD + URA + LEU
A	+	+	+	+	+	+	+	+
B	+	-	-	-	-	+	-	-
C	+	-	-	-	-	-	+	-
D	+	-	-	-	-	-	-	-