Isolation of Genomic DNA

• Cell lysis


  1. Cell membrane is disrupted physically or chemically

  2. Fluid containing all the cell components including DNA is obtained
• Lysate


  Fluid obtained after cell lysis containing all the cell components
• Breaking down cell components during cell lysis


  1. Lipids are broken down by detergents and surfactants

  2. Proteins are broken down by protease

  3. RNA is broken down using RNase
• Concentrating lysate


  1. Lysate is treated with concentrated salt solution

  2. Broken components clump together

  3. DNA freely floats in the solution
• Separating DNA from debris


  1. Solution is centrifuged

  2. Clumped debris is separated from DNA
• DNA precipitation


  1. Ice cold alcohol plus a salt is added to increase ionic strength

  2. DNA precipitates out
• DNA pellet


  Pellet of DNA obtained after centrifugation
• Suspending DNA pellet


  1. Pellet is suspended in slightly alkaline solution mostly TE buffer or ultra-pure water

  2. For subsequent DNA experimentation usually PCR