Agarose Gel Electrophoresis

Introduction

• Presenter: Dr. Alex Danis, Mini PCR Bio
• Common method for visualizing and identifying DNA fragments
• Gel electrophoresis: movement of molecules mobilized by electricity through a substance

Basics of Electrophoresis

• Uses two electrodes: positive and negative
• Creates an electric field across the gel
• Molecules move based on size and charge:
  • Positively charged: move towards negative electrode
  • Negatively charged: move toward positive electrode (e.g., DNA)
  • Neutral molecules: do not move

Principle of Gel Electrophoresis

• Separates DNA fragments by size using a gel with pores
• Short DNA fragments move quickly
• Longer DNA fragments move slowly due to more obstacles
• Allows for separation of DNA based on size

Preparing Agarose Gel

• Made from agarose, a polysaccharide from seaweed
• Process: dissolve powder in liquid, boil, cool and thicken in a mold
• Add a DNA stain for visualization

Loading DNA Samples

• Use a comb to create wells in the gel
• Gel placed in electrophoresis chamber with running buffer
• DNA mixed with loading dye (more dense than buffer)
• Dye helps visualize loading and track movement

Running Electrophoresis

• Load samples into wells, close lid, turn on power
• Use BlueGel from Mini PCR Bio for electrophoresis and visualization
• Gel runs for about 20 minutes

Visualizing DNA

• DNA stains bind to DNA and make it visible
• Use fluorescent stains and a safe blue light for visualization
• Lanes represent DNA samples; bands indicate DNA fragments of identical size

DNA Size Determination

• Add a DNA ladder (known lengths) for comparison
• Determine sizes of DNA fragments by comparing bands to the ladder

Applications

• Identifying specific DNA fragments
• Confirming DNA identity, infection, or individual (DNA fingerprinting)
• Useful for post-PCR analysis

Conclusion

• Gel electrophoresis: crucial tool in molecular biology labs
• Efficient, easy, economical with Mini PCR Bio systems
• Additional resources and learning labs available at minipcr.com