Techniques used to test native DNA

Several techniques commonly are used to test native high-molecular- weight DNA obtained from cells and tissues, including the Southern blot, dot and slot blot procedures, and in situ hybridization of tissue sections with oligonucleotide probes. These techniques work well when there is an adequate amount of fresh tissue or cells available to provide a source for the intact DNA. These techniques involve separating, or denaturing, the double-stranded DNA into individual strands, and then applying a marked nucleotide probe and allowing it to hybridize to a complementary DNA sequence that may be present. These techniques are used to determine whether a particular DNA sequence is present.