Technology
Pulsed-field gel electrophoresis (PFGE) is a method used to separate proteins or high molecular weight linear DNA fragments that are greater than 50 kilobases (kb) in size. Fragments are separated by pulsing an electrical field across an agarose gel rather than applying the constant field used in conventional electrophoresis.
Diagnostic Methods
Technology
A DNA sequencing method that uses a "sequencing by synthesis" strategy. The strand complementary to a template is synthesized a single base at a time through the sequential addition of individual solutions of each base. Incorporation of a base into the growing strand generates free pyrophosphate that is detected as light, as generated by a luciferase-catalyzed reaction.
Diagnostic Methods
Technology
Variation occurring within a species in the length of DNA fragments generated by a specific endonuclease. Such variations are generated by mutations that create or abolish recognition sites for these enzymes.
Diagnostic Methods
Technology
A laboratory procedure in which an RNA strand is first transcribed into a DNA complement and then subjected to PCR amplification. Transcribing an RNA strand into a DNA complement is termed reverse transcription and is done by the enzyme reverse transcriptase.
Diagnostic Methods
Technology
The process of arranging protein, DNA or RNA sequences to identify regions with similar sequences that may elucidate functional, structural, or evolutionary relationships between the sequences.
Diagnostic Methods
Technology
A rapid, simple, visual and sensitive technique for measuring DNA breakage in individual mammalian cells in response to a test agent. A cell is immobilized in agarose and made permeable and the broken DNA migrates out under the influence of the electric field. A damaged cell has the appearance of a comet with a brightly fluorescent cell body and a tail whose length and fluorescence intensity are related to the number of DNA-strand breaks induced by the test agent.
Diagnostic Methods
Technology
A technique for the detection of specific DNA fragments that have been separated by polyacrylamide-gel electrophoresis, transferred to a nitrocellulose or other type of paper or nylon membrane, and detected by hybridization and visualization with a labeled probe.
Diagnostic Methods
Technology
A procedure used to demonstrate nucleotide sequence variations that occur in the same region of DNA between individuals within a species, or between alleles in an individual to detect mutations in various genes, such as oncogenes, tumor suppressor genes, or genes responsible for genetic diseases. The method detects different conformations adopted by partially denatured DNA fragments resulting from their specific nucleotide sequences under denaturing conditions. Denatured single-stranded DNA fragments are allowed to partially renature without formation of double-stranded DNA. The particular conformations adopted by each of the renatured fragments depend on each of their specific nucleotide sequences. The fragments are run on polyacrylamide gels to detect subtle changes in migration due to their particular secondary structures. Resulting fragment band in the gel will misalign if any point mutations are present to alter the conformation.
Diagnostic Methods
Technology
An isothermal, in vitro nucleic acid amplification method that allows primer-directed amplification of a target sequence. It utilizes a primer that can be nicked to create a polymerase start site and a DNA polymerase that will displace a downstream strand as it tracks along the template.
Diagnostic Methods
Technology
Technology that detects differences between an individual's DNA sequence and a reference DNA sequence.
Diagnostic Methods
Technology
A procedure that can determine the DNA sequence for all of the exons in an individual.
Diagnostic Methods
Technology
Any technique designed to amplify a limited genomic DNA sample so as to generate a new sample that is indistinguishable from the original but with a higher DNA concentration.
Diagnostic Methods