The Basis for Electrophoresis

DNA profiling has been popularized in the news and television shows as a way of determining paternity or catching a criminal. Today students learned about gel electrophoresis, a scientific technique in which electrical current is used to separate charged molecules in a gel matrix (e.g., similar to gelatin) based on their size. This scientific method is routinely used to separate DNA and is the first step in the process of DNA profiling. Since any appropriately sized charged molecule can be separated by gel electrophoresis, students used this technique to separate the food dye molecules in the colored candy coating of Skittles and M&Ms and determined what food dyes make up each candy color. Students also simulated a DNA profiling procedure using commonly found craft objects, ran a race to demonstrate the sieve nature of the gel matrix and analyzed a fictitious case study of a DNA profile, all in one class!