Yeast Mutagenesis

Mutagenesis Lab

Procedure  

1.

Clean your hands and work area.

• Clean your hands

with hand sanitizer

• Put all the food

away

2.

Acquire a Petri dish from your instructor and label it using a waterproof

marker.

• Write your name in

small letters around the outside edge of the bottom of the dish.

• Draw lines on the

bottom of the dish to divide it into 3 parts.

•

Label one area “control”.  What is a control and why do you need it? What

is your control?

•

Label each area on the bottom of the dish.

•

Write in small letters around the edge.

3.

Pick a mutagen.

•

Discuss with your partner what mutagen you want to test. You can test the same

mutagen as last time or pick a different one from the collection provided by

your instructor. Note that if you want to test your own mutagen, you should

first talk to your instructor!

•

Label one of the remaining two thirds of the Petri dish with the name of the

mutagen you chose.

4.

Modify the protocol

For

the last third of the Petri dish you will modify the protocol in a way that

will make your mutagen stronger or weaker!

Option A: Yeast Protection

•

Discuss with your partner how you can modify the described about mutagenesis

with your substance of choice in order to make it less mutagenic. You

can:

->

add less mutagen (less than 2 drops of liquid or a scoop of powder/solid)

->

incubate for less than ten minutes

->

add another substance in addition to the first one

->

protect from sunlight

->

use your imagination!

•

Write down the modifications you’ll make to the protocol.

Option B: Stronger mutagenesis  

•

Discuss with your partner how you can modify the described about mutagenesis

with your substance of choice in order to make it more mutagenic. You

can:

->

add more mutagen (more than 2 drops of liquid or a scoop of powder/solid)

->

incubate longer than ten minutes

->

add another mutagen in addition to the first one

->

expose to sunlight

->

use your imagination!

•

Write down the modifications you’ll make to the protocol.

5.

Acquire yeast from your instructor.

•

Label the tubes and the pipettes -> A: control, B: your

mutagen, and C: modified mutagen.

•

Swirl the container of yeast.

•

Add water (2 drops) to the control yeast (tube A).

•

Add your mutagen of choice to the second tube with yeast (tube B). If

your mutagen is liquid (shampoo, hot sauce, etc.), add 2 drops. If your mutagen

is very viscous, powder or solid (toothpaste, splenda, etc.), pick a small

amount with a toothpick and add to the yeast container.

•

If you are modifying the amount of mutagen added to the third container (tube C),

add the altered amount (more, less, in combination with another mutagen, etc.).

Otherwise, add the same amount of mutagen as in tube B.

•

Incubate the yeast for 10 min.

Note: if you are altering the incubation time for

tube C (incubate for more or less than 10 min), incubate that tube accordingly!

 

•

Acquire a questionnaire from your instructor and fill it in while waiting.

Return your completed worksheet to your instructor when you finish!

•

After the incubation, transfer the yeast solution with a sterile pipet on the

media on the corresponding thirds of the plate.

•

Gently spread the liquid with a toothpick.

•

Let it dry for 5 min.

•

Return the plate to your instructor

6.

Return the plate to your instructor. He/she will place it at 30C for the next

3-4 days and allow the yeast to grow.