DNA isolation and Southern analysis: a clinician's view.

DNA isolation and Southern Blot analysis are two of the many techniques currently being used routinely by molecular biologists to discover genetic defects that affect human health. Together these two techniques have greatly aided in the growing knowledge of genetics on a molecular level. Southern blotting can be used to discern genetic deletions, alterations, or amplifications that are not detectable by cytogenetic methods. Several examples of the clinical applications of these methods are discussed in Table 4. Southern analysis has been recently used: (1) to facilitate prenatal diagnosis of sickle cell hemoglobinopathies, (2) to demonstrate human papillomavirus DNA integration in the genome of cervical cancer cells and (3) to demonstrate that oncogene amplification in the tumors of patients with node positive breast cancer correlates inversely with prognosis. Each of these examples not only have diagnostic value for patient care but also may help begin to understand the very basis of the disease processes themselves.