Using Protein Gel Electrophoresis to Study Evolution

A CIBT Lab Exercise in Molecular Biology



Students will separate a mixture of proteins from skeletal muscle using SDS-polyacrylamide gel electrophoresis (PAGE). PAGE is a poerful analytical technique having numerous applications in modern biology. Evidence for evolutionary relatedness amongst organisms can be determined using this technique. Suggested organisms to compare include various fishes, mammals, poultry and/or sea foods, all of which are available from the grocery store. During the laboratory, students will develop an experimental design, prepare samples of muscle tissue from various organisms, observe the process of electrophoresis and analyze their results. Analysis consists of comparing protein bands according to their molecular weights on the gel.


Appropriate Levels

Life Science, High School, Honors, or Advanced Placement Biology.


Time Required

Teacher Prep: Significant, includes a trip to the grocery store.
Student Time: Either a full day in-school field trip or four 45 min. class periods; if the second option is chosen, either the teacher or students need to be available between classes and/or after school to turn off the gels and prepare them for staining at the end of the third day.



Protein Gel Electrophoresis apparatus: (The number of electrophoresis setups required will vary depending on class size).

  • Vertical gel boxes w/ tray inserts and stands.
  • 1 Thermometer
  • Power supplies and extra fuses
  • Staining trays with lids.
  • 1 Dry Bath Heater.
  • Precast polyacrylamide gels (refrigerate upon arrival).

Reagents and Gel Photography Supplies

  • 2 Bottles Tris-SDS solulibization buffer.
  • Camera
  • 2 Bottles protein- fixative stain
  • Lightbox
  • 1 Vial of high molecular weight markers (freeze upon arrival)
  • Polaroid film- enough film for one picture per gel, more film can be purchased from WARD’S Natural Science Establishment (1-800-962-2660).
  • Polaroid film type 667 can be purchased in packs of ten exposures (#25 W 1135, $28.85).
  • different meats
  • distilled water (1 liter per gel)

General Lab Supplies

  • 1 or 2 liter flask or beaker
  • Labeling tape
  • 2 liter flask (one per 6 groups of students)
  • 4 markers
  • 2000 ml graduated cylinder (at least one per class)
  • razor blades or scalpels
  • transfer pipettes (5-6 per muscle sample)
  • mortar and pestles (1 per muscle sample)
  • 1 Container capillary micropipettes & 6 stainless steel plungers
  • 1 Spatula
  • glass rods
  • safety glasses
  • Test tubes (16 mm)
  • Latex Gloves
  • Clinical centrifuge or funnel with cheesecloth (one for whole class)
Copyright for this material is held by Cornell University, the Cornell Institute for Biology Teachers (CIBT), the Center for Nanoscale Systems Institute for Physics Teachers (CIPT), and or West Hill Biological Resources, Inc., 2014. This work may be copied by the original recipient from this web site to provide copies for users working under the direct supervision of the original recipient. All other redistribution of this content without the express written permission of the copyright holder(s) is prohibited.

Price: No Charge

Marcia Cordts and Meredith Kusch, Cornell University, Ithaca, NY

Nancy Ridenour, Ithaca High School, Ithaca, NY

Mary Colvard, Cobleskill High School, Cobleskill, NY

Harriet Bongiorno, Union-Endicott High School, Endicott, NY