DNA for analysis is purified using salt precipitation. The method is gentle, limits the breakage of the long chromosomal strands, and avoids the use of phenol and chloroform. It is suitable for use with cultured cells, breast tumor tissue that has been subjected to hormone receptor analysis, and blood samples. The loss of heterozygosity assay is performed using a multiplex PCR, in which one of each primer pair is labeled with a different fluorophor. - [Read A Multiplex PCR Method to Define a Narrow Deleted Chromosomal Region of a Tumor Genome]
Protocol describes a method for DNA fragmentation by sonication. During sonication, DNA samples are subjected to hydrodynamic shearing by exposure to brief periods of sonication. DNA that has been sonicated for excessive periods of time is extremely difficult to clone. - [Read Fragmentation of DNA by Sonication Protocol]
In this protocol, bacterial cells are lysed by being subjected to short, intense treatments with ultrasound, which breaks the cell walls and shears the DNA into sizes that will not affect the viscosity of the samples. Note that this method causes some denaturation of the samples. The resulting lysate is ready for preclearing. - [Read Immunoprecipitation: Lysing Bacteria by Sonication Protocol]