profiling has become a standard technique in criminal investigations because
scientists are able to extract what is in effect an identity card from
the smallest samples of biological material - such as a single hair or
a drop of blood. However, laboratories involved in forensic DNA profiling
across Europe have developed a range of methods and techniques over recent
years, the results of which are often incomparable. Standardisation means
that although serial offenders may be able to run, they will not be able
acid) is the genetic material found in the cells of all living things
and, with the exception of identical twins, the complete DNA of an individual
is unique. DNA typing - also known as DNA fingerprinting - is used to
identify criminals by comparing fragments of DNA extracted from biological
samples found at the crime scene, such as hair, blood and sperm, to that
need for standardisation
progress in this area has advanced rapidly over recent years and
has resulted in different forensic laboratories using different
techniques and typing systems. In addition, there are many different
genetic markers that can be analysed. As a result, it has not only
proven difficult to compare data from one laboratory with that of
another, it is also difficult to check the quality of laboratory
work - essential when people's future freedom may rest on the findings.
clear need for standardisation is being addressed in a three-year
programme of work being funded by the European Commission. Scheduled
to end in August 2000, the STADNAP
project brings together 20 forensic laboratories and other related
organisations from 16 European countries, and is being led by the
Institute of Forensic Medicine (IFM) at the Universidade de Santiago
de Compostela, Spain.
To achieve its objectives, the partners have divided themselves
into four working groups:
the state of the art
group one was tasked with a survey of the current state of the
art, and has identified the key markers and technologies recommended
for use by the forensic community.
In addition, the group has also been looking at new technologies
and identified certain problems that will need to be addressed
in future. For example, some of the emerging technologies are
complicated and require the use of expensive equipment not normally
found in laboratories; this is likely to be a stumbling point
for widespread introduction. The group is therefore emphasising
the need for STADNAP to maintain close contacts with R&D-based
organisations to promote standardisation while encouraging the
development of new techniques.
out transnational comparisons
group two has been carrying out comparison exercises, and has
demonstrated the reliability of transnational data comparisons
for both Y chromosome analysis and another important marker, mitochondrial
DNA (mtDNA), by sending out control samples to participating laboratories.
The group has also produced recommendations and guidelines for
the scientific community regarding the use of mtDNA and Y chromosome
polymorphisms in forensic casework.
In addition, the group has examined the lack of suitable control
samples to compare the efficiency of different analysis systems.
In forensic science, DNA samples have often been degraded by ultraviolet
light, humidity and decay. Experiments to determine the best way
to provide control samples of degraded DNA have been carried out
at the Institute fur Rechtmedizin, part of the Johannes Gutenberg
Universitate Mainz in Germany. The experiments are almost complete,
and it is hoped that a commercial company will step forward to
make the required quantities of degraded DNA available.
group 3 has concentrated on technology transfer between the partners,
in addition to setting up a web site to promote the work of STADNAP.
Seven visits of up to two weeks in duration have enabled various
partners to visit the laboratories in other countries. "The
exchanges of personnel between labs has proven to be a valuable
instrument for the development of common standards, and ten further
exchange visits are being planned," says Professor Angel
Carracedo of the IFM.
Also as part of the technology transfer work package, STADNAP
has recently launched a fellowship
programme inviting applications from laboratories who wish
to extend their level of expertise in forensic DNA testing and
believe they could benefit from a period of training at one of
the member laboratories of STADNAP.
group four set out to compile two anonymous population databases
to help analyse population variations across Europe and to facilitate
adequate estimates of gene frequencies in forensic casework. One
of the databases is for mtDNA, the other is for short tandem repeated
polymorphisms, sections of DNA which, as their name implies, contain
repeated sequences that can be used for identification purposes.
The databases will eventually be made available through the Internet
and also as CD-ROMs.
thematic network has been set up under the Measurements
and testing generic activity to standardise DNA profiling
project will help to ensure that mobile serial offenders can be
readily identified across national borders, and provide a check
on the quality of laboratory results.
- Standardisation of DNA profiling techniques in the European