- Course Introduction
- 01: Evidence & DNA
- 02: Forensic Biology
- 03: DNA Extraction & Quantitation
- 04: DNA Amplification
- 05: Amplified DNA Product Separation
- 06: STR Data Analysis & Interpretation
- 07: Population Genetics & Statistics
- 08: Communicating Results
- 09: Other DNA Markers & Technologies
- Course Resources
- Laboratory Training Manual
President's DNA Initiative
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Advancing Justice Through DNA Technology
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Advancing Justice Through DNA Technology
DNA Analyst Training
Variable Number of Tandem Repeats (VNTRs)
Home > Evidence & DNA > DNA > DNA Typing by RFLP Analysis > Variable number of Tandem Repeats (VNTRs)
Since each VNTR region consists of repeats of a specific sequence of bases, complementary oligonucleotides can be synthesized. These oligonucleotides, when labeled with a marker such as P32 or a chemiluminescent compound, are known as probes.
There are five basic steps to developing DNA profiles using VNTRs:
- Extracting DNA
- Cutting DNA into fragments using restriction enzymes
- Separating the fragments based on size using gel electrophoresis
- Transferring the fragments to a nylon membrane (southern blotting), causing immobilization
- Locating and identifying the fragments by applying a solution containing the probe of interest, which then hybridizes to the immobilized DNA. Visualization of the fragments requires a lengthy exposure of the probe to a detection system and can add several days to the assay time.
