DNA-fingerprinting
DNA analysis
The Laboratory of Pharmaceutical Biotechnology performs human identification using DNA profiling techniques, mainly for the Department of Justice in Belgium. The laboratory is recognized by the Department of Justice as a forensic DNA laboratory in criminal cases and has a BELAC accreditation since September 15th, 1996.
DNA profiling can be very useful not only in forensic casework but also in paternity testing.
By combination of short tandem repeat loci (STR) in multiplex polymerase chain reactions (PCR), individuals can be identified with very high levels of certainty. Using PCR technology, profiles (and thus identification) can be obtained of very minute and old, badly stored samples.
A DNA profile can be obtained from almost any kind of biological material (e.g. blood(stains), saliva(stains), sperm(stains), skin debris, hair, biological tissues, bones, teeth, ...).
In our laboratory a total of 19 STR loci can be analyzed including the 12 ESS loci (the European Set of Standard loci: D3S1358, vWA, FGA, TH01, D21S11, D8S1179, D18S51, D10S1248, D1S1656, D12S391, D2S441 and D22S1045). The remaining 7 STR loci are TPOX, D16S539, D13S317, D5S818, D7S820, SE33 and CD-4. In addition, sex determination can also be performed by analyzing the amelogenin locus on the X- and Y-chromosome. All STR loci are analyzed on an ABI3130xL and/or ABI3500xL genetic analyzer.
Besides the commercially available kits we also created 2 multiplexes of respectively 15 and 9 STR loci in our laboratory. Those 2 multiplexes have 4 STR loci in common, what gives an extra control on the obtained profiles. These multiplexes are extensions of our original multiplex described and published in 1998 in the scientific journal Electrophoresis. The great sensitivity and specificity of this multiplex (which is better than the available commercial kits) was presented on the Second European Symposium on Human Identification in June 1998 in Innsbruck (DNA typing of fingerprints on skin debris: Sensitivity of Capillary Electrophoresis in forensic applications using multiplex PCR).
In special and very urgent cases, DNA identification can be performed within 24 hours after receipt of the samples (max. 2-3 samples). The regular cases are performed in max. 1 month (in fact, in 16 calendar days on average).
A part of the analysis is automated using liquid handlers, avoiding human errors in this way. There is one liquid handler for pre-PCR set-up; a second one is used for processing post-PCR samples.
Besides autosomal STR analysis, we also perform Y-STR analysis. We created a multiplex of 8 STR loci: DYS 19, DYS385a/b, DYS 389I, DYS 389II, DYS390, DYS391, DYS392 and DYS393. This way the minimal haplotype is determined. A commercial kit containing 3 extra loci (DYS437, DYS438 and DYS439) besides the 8 STR mentioned above is also used.
Our lab can also perform analysis of mitochondrial DNA (mtDNA), specifically on samples where nuclear typing has failed or cannot be performed such as hair without a root.
A P.A.L.M. microdissection laser microscope is available in the laboratory. Using the laser microdissection technique, individual cells can be isolated very specifically. Sperms cells, for example, can be isolated from post coital samples. Our laboratory has already published several scientific articles on this subject in a.o. “International Journal Of Legal Medicine”.
DNA research
Besides the routine DNA typing for the Department of Justice, our lab performs research in the field of DNA analysis in order to optimize and improve the procedures. This research includes:
- optimisation and expansion of the use of P.A.L.M. microlaser system in forensic cases
- optimisation of DNA extraction
- statistical interpretation of the data
Scientific articles
The publications produced by our laboratory in various scientific journals can be consulted using the following links:
- selection of forensic publications: see 'Publicaties' on Forensisch Instituut
- all research publications: see Ghent University Academic Bibliography