Diagnostic and Clinical Applications of DNA

The ability to isolate specific fragments of DNA containing known sequences of genes gives rise to DNA probes that can be used for a variety of diagnostic, forensic, and therapeutic purposes. DNA probes can be labeled with either radioactive or nonradioactive markers. A DNA probe 

The use of DNA probes in various aspects of medical diagnostics is increasing rapidly. DNA probes can be used to identify infectious agents if sequences specific to different pathogens are known. Identification of a pathogen by DNA probes can be done in hours as compared to days or weeks by conventional culturing of microorganisms. 

DNA probes are now used routinely to detect the presence of mutant alleles in fetal cells obtained by amniocentesis, as well as in cells removed from affected adults or carriers. Many inherited disorders, such as sickle cell disease, cystic fibrosis, Huntington s disease, Duchenne s muscular dystrophy, and dozens of other Mendelian (single-gene) disorders, can now be diagnosed in fetuses and adults. In addition to inherited disorders, DNA probes are used to detect the presence of active oncogenes or inactive tumor suppressor genes in cancerous tissues removed from patients (Chapter 26). 

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