RFLP
Definition
Restriction Fragment Length Polymorphism. The first-generation DNA typing method using restriction enzymes and Southern blotting. Required nanograms of intact DNA.
- Full name
- Restriction Fragment Length Polymorphism
- Generation
- First-generation forensic DNA typing method
- Method
- Restriction enzymes and Southern blotting
- Sample requirement
- Nanograms of intact, high-quality DNA
Common questions
Why was RFLP largely replaced by PCR-based STR typing in casework?+
RFLP required relatively large amounts of high-molecular-weight DNA and could take weeks to complete, while PCR-based STR methods work on degraded or trace samples, need far less material, and produce results in a fraction of the time.
Can RFLP results still be compared to modern STR profiles?+
No, RFLP and STR typing target different genetic loci and produce results in incompatible formats, so an old RFLP profile cannot be directly matched against a modern STR database entry without separate re-analysis.
Is RFLP data still relevant in current casework?+
It mainly appears in archived case files or historical convictions from before the mid-to-late 1990s, so its relevance today is largely in post-conviction review, requiring original evidence to be retested with modern methods for current comparisons.
Related terms
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- Chromosome
- A discrete, condensed structure consisting of a single long DNA molecule complexed with histone proteins. Humans normally carry 46 chromosomes in 23...
- CODIS
- The FBI's Combined DNA Index System, the US national STR-based forensic DNA database. Contains profiles from convicted offenders, arrestees, and unidentified crime-scene...
- Multiplex STR Kit
- Single-tube PCR amplifying 15+ STR loci plus amelogenin in one reaction. AmpFISTR Identifiler Plus and PowerPlex are the workhorses in Indian DNA...
- Nucleotide
- The monomer unit of nucleic acids. Each nucleotide consists of a five-carbon sugar (deoxyribose in DNA, ribose in RNA), a phosphate group,...
- PCR
- Polymerase Chain Reaction. Kary Mullis 1983. Exponential amplification of a target sequence using a thermostable Taq polymerase, two primers and thermal cycling.
- SNP (Single Nucleotide Polymorphism)
- A position in the genome where the nucleotide base differs between individuals. Genome-wide SNP panels are more powerful than STR panels for...
- STR (Short Tandem Repeat)
- A genomic locus where a 2, 7 base-pair unit is repeated in tandem a variable number of times between individuals. The variation...
- VNTR
- Variable Number Tandem Repeats. Longer repeat units (10 to 100 bp) than STRs. The original Alec Jeffreys 1984 fingerprinting markers, now superseded...
- Watson-Crick Base Pairing
- Adenine pairs with thymine via two hydrogen bonds; guanine pairs with cytosine via three. The pairing rule that makes the double helix...