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In this activity, learners extract DNA from their own cheek cells, then create a rudimentary DNA profile similar to those seen on crime scene dramas. This step by step guide includes instructions and photographs that detail how to build an electrophoresis chamber. Learners can follow the directions to mix three buffer solutions, extract DNA from saliva, and prepare, run, and stain their gel in their electrophoresis chamber.

Quick Guide

Preparation Time:
30 to 45 minutes

Learning Time:
1 to 7 days

Estimated Materials Cost:
Over $20 per group of students

Age Range:
Ages 11 - adult

Resource Types:
Activity, Experiment/Lab Activity


Materials List (per group of students)

  • test tube or similar container (sometimes available with aquarium testing kits)
  • table salt
  • baking soda
  • bottled water
  • paper cup
  • liquid soap (colorless preferred)
  • isopropyl alcohol, 99%, pre-chill in freezer overnight
  • agar (a.k.a. agar agar, available in oriental food stores)
  • aquarium pH kit
  • toothpicks
  • Legos (to build one version of buffer chamber, and to build casting comb)
  • 2 stainless steel screws, 5 mm
  • stainless steel wire
  • plastic container (to act as buffer chamber)
  • glycerine/glycerol
  • red food coloring
  • methylene blue (aquarium antimicrobial)
  • beakers
  • graduated cylinder and other measuring tools
  • plastic travel soap dish
  • Glad Press 'n' Seal wrap
  • scissors
  • hot plate
  • stirrer
  • masking tape
  • 5 to 7 9V-batteries
  • alligator clips


  • Engineering and Technology
    • Engineering
      • Bioengineering/Biomedical Engineering
    • Technology
      • Medical Technology
      • Agriculture and Biotechnology
  • Life Sciences
    • Cells
    • Heredity and Genetics
      • Human Genetics
      • DNA Structure and Function
  • Physical Sciences
    • Electricity and Magnetism
      • Electric Circuits
    • Chemistry

Informal Categories

  • Crime Science


To use this activity, learners need to:

  • see
  • see color
  • read
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Access Rights:

  • Free access



  • All rights reserved, Make Projects, 2011