Which techniques involve nucleic acid hybridization

This technique is used to detect the presence of DNA from pathogens in clinical specimens and to locate specific genes in cells. DNA hybridization takes advantage of the ability of nucleic acids to form stable, double-stranded molecules when two single strands with complementary bases are brought together under favorable conditions. Figure DNA hybridization.

The single strands of DNA are then attached to a solid support such as a nitrocellulose or nylon membrane so that the strands do not reanneal Figure The DNA is attached to the membrane by its sugar-phosphate backbone with the nitrogenous bases projecting outward.

This allows the formation of hydrogen bonds between complementary bases. The probe, so called because it is used to seek or probe for DNA sequences, is labeled with a reporter group, which may be a radioactive atom or an enzyme whose presence can be easily detected.

The probe is allowed to react with the target DNA ; then any unreacted probe is removed by washing in buffered solutions. After the washes, all that remains on the nitrocellulose is the target DNA and any probe molecules that have attached to complementary sequences in the target DNA , forming stable hybrids.

Hybridization of target and probe DNA s is detected by assaying for the probe's reporter group. If the reporter group is detected, hybridization has taken place. If no reporter group is detected, it can be assumed that the target molecule does not have sequences that are complementary to those of the probe, and hence, the gene or DNA segment sought is not present in the sample. Three common formats are used in solid-phase hybridization assays; dot blot, Southern blotting, and in situ hybridization.

In the dot blot assay, a specified volume of sample or specimen is spotted onto a small area of nitrocellulose membrane, which is then carried through the procedure described above. Nucleic Acid Hybridization Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Kendrew, Encyclopedia of Molecular Biology, , p Year introduced: PubMed search builder options Subheadings: adverse effects classification drug effects economics epidemiology ethics etiology genetics history immunology instrumentation methods mortality organization and administration pharmacology physiology radiation effects standards statistics and numerical data therapeutic use trends veterinary.

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