The Arizona Hedgehog Cactus:
Endangered Species or not?

Lesson 7: Pour and Load Agarose Gels

Purpose: Students will gain experience in actually pouring an agarose gel and loading the DNA into the wells to perform a genetic analysis of variation among individuals and between populations.

Time: One 90-minute class period or two 50-60 minute periods

Materials Preparation:

• 100X electrophoresis buffer stock
• Deionized water
• 100 ml and 1000 ml graduated cylinders
• Methylene blue or ethidium bromide dye
• Centrigram balance
• Agarose
• Large test tubes
• Casting trays with combs (and glass plates if necessary)
• Masking tape
• Plastic pipets
• Boiling water bath

Student Objective(s):

• Prepare and pour an agarose gel.
  
• Load DNA samples into the wells of the gel.

Lesson Plan:

(1) Students follow the instructions contained in the hand-out "Electrophoresis Protocols" to prepare and pour one agarose gel per group of 3-4 students.

(2) Give each student a sample of amplified DNA from one individual plant from the Cochise county population or the Pinal county population. Each student will load his/her DNA sample into one of the wells in the gel.

(3) Explain that after all DNA has been loaded onto the gel, the electric current will be turned on and the DNA will be electrophoresed through the gel overnight. When finished, the gels will be placed in the methylene blue or ethidium bromide dye to stain the DNA bands within the gel.

Supplemental Materials:

• "Electrophoresis Protocols" - Directions
  

The University of Arizona
Department of Biochemistry and Molecular Biophysics
General Biology Program for Secondary Teachers
warder@email.arizona.edu