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DNA Extraction and Quantitation for Forensic Analysts

Solubilization of Stain Components

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Step One: Solubilization of Stain Components

Water must be replaced so that dried stains can be resolubilized for DNA extraction procedures. The DNA is protected from unnecessary degradation in this process by adding EDTA, a magnesium chelator, to the lysis buffer. EDTA prevents nucleases from degrading the DNA. Tris (a component of the buffer) interacts with the lipopolysaccharides present on the outer cell membrane, which helps to make it permeable. This effect is enhanced with the addition of EDTA.06

Step One Reagents

Stain extraction buffers are usually slightly alkaline and generally contain Tris base or Tris-HCl (pH between 7.5-8.0), EDTA, and sodium chloride (NaCl).

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