This activity provides a first-hand understanding of how DNA can be isolated for further analysis, such as DNA fingerprinting. Students also reinforce their understanding of cell structure and biological macromolecules. We use a kiwifruit protocol because it uses commonplace materials and requires little equipment. Students use agarose gel electrophoresis to determine the composition of different biological dyes or food coloring agents. This activity helps students learn how molecules can be separated and identified by electrophoresis.
Students perform agarose gel electrophoresis to analyze DNA samples from a mock crime scene.
Based on DNA fingerprinting profiles that are simulated to represent the two suspects, the victim, and DNA from the crime scene, students determine which suspect likely committed the crime. This activity helps students understand how DNA variation in individuals can be analyzed in practical applications such as genetic testing and forensics. Students examine the genetic model organism C. elegans, a small soil nematode, and characterize the phenotypes of different C. elegans mutants. By analyzing the DNA products using agarose gel electrophoresis, students identify the genotypes of the C. elegans mutants. This activity helps students understand how PCR is used as a rapid method for DNA-based diagnosis in applications such as pathogen detection or predisposition to genetic disease.