Agarose Gel / Agarose Gel Electrophoresis

Agarose Gel Electrophoresis (AGE) is a common molecular biology technique used to separate nucleic acids (DNA & RNA) based on their size (length in base pairs).

🔍 What is Agarose?

• Agarose is a polysaccharide obtained from red algae (seaweed)

• It forms a porous, jelly-like matrix when heated and cooled in buffer

• The pore size depends on agarose concentration

  • Higher % agarose → smaller pores → separates smaller DNA

  • Lower % agarose → larger pores → separates bigger DNA

⚡ Principle of Agarose Gel Electrophoresis

1. DNA is negatively charged due to its phosphate backbone

2. When an electric field is applied:

   • DNA migrates from negative (cathode) → positive (anode)

3. Smaller fragments move faster & farther, larger fragments move slowly

➡ Separation is based on size (NOT charge)

🧪 Steps of Agarose Gel Electrophoresis

📌 Interpretation

Usually compared with DNA ladder / marker to determine fragment size.

📍 Concentration of Agarose Gel & Usage