DNA101 Lab: Rainbow Gel Electrophoresis

Practice using DNA separation technology with food coloring!

UPDATE (9/22/2017): A version of this Learning Lab is now available in the miniPCR store

You may think the technology used to match DNA samples, such as solving a crime by matching fingerprints, is very complicated and can only be used to analyze DNA. However, this process, called gel electrophoresis, can actually be used to look at the size and charge of many molecules. In gel electrophoresis, samples are put in an environment where they move different distances based on their size and charge; differences in their movement can reveal information about the molecules.

The gel, usually made of agarose, acts as a sieving medium, retarding the passage of molecules. Smaller molecules move farther in the gel because they have an easier time moving through the gel, while larger molecules move more slowly. Similarly, positively charged samples move towards the negatively charged pole, while negatively charged samples move towards the positively charged pole. These two principles allow for comparison of any samples based on size and charge. So while gel electrophoresis is a process used in complex DNA comparisons (like DNA fingerprinting forensics, genotyping, and genetic diagnosis of diseases), it can also be done in your kitchen to separate food coloring!


miniPCR is excited to share a new lab that allows people to understand DNA technology using fun colors available in your house. This lab uses student-friendly language to explain gel electrophoresis and DNA analysis, while making those concepts simple by applying them to food dyes. Green food coloring will divide into yellow and blue sections on the gel, just as a longer piece of DNA would divide into smaller segments based on its sequence.

Through gel electrophoresis of food dye, this lab makes the basic components of DNA analysis accessible to everyone (and visually appealing!).

This free lab is now available for download through this PDF link and under DNA 101 Labs in the miniPCR Downloads Center.