There are several methods for extracting genetic material (nucleic acid {DNA and/or RNA}) from samples. The most common protocols are manual or automated which essentially have the same principles:
Lysis of sample material. Nucleic acids are released and nucleases are denatured.
Binding of nucleic acids to a membrane surface such as silicates. This binding is facilitated by the chaotropic salt conditions and high ionic strength of the lysis/binding buffer.
Separation of membrane bound nucleic acid from residual lysed sample.
Removal of unbound substances (proteins, cell debris, and PCR inhibitors) by several washing steps.
Elution of purified nucleic acid from the membrane.
