Biology Reference
In-Depth Information
Ladder
Ladder
Ladder
K562
K562
Figure 1.4
Minisatellite analysis using a single locus probe: ladders were run alongside the tested
samples that allowed the size of the DNA fragments to be estimated. A control sample labelled
K562 was analysed along with the tested samples
The PCR increases the sensitivity of DNA analysis to the point where DNA profiles
can be generated from just a few cells, reduces the time required to produce a profile,
can be used with degraded DNA and allows just about any polymorphism in the
genome to be analysed.
The first application of PCR in a forensic case involved the analysis of single
nucleotide polymorphisms in the human leukocyte antigen (HLA)-DQ
α
locus (part
of the major histocompatibility complex (MHC)) [77] (see Chapter 12). This was
soon followed by the analysis of short tandem repeats (STRs), which are currently
the most commonly used genetic markers in forensic science (see Chapters 6 - 8).
The rapid development of technology for analysing DNA includes advances in DNA
extraction and quantification methodology, the development of commercial PCR-
based typing kits and equipment for detecting DNA polymorphisms.
In addition to technical advances, another important part of the development of
DNA profiling that has had an impact on the whole field of forensic science is
quality assurance. The admissibility of DNA evidence was seriously challenged in the
USA in 1989 -
People
v.
Castro
[78]; this and subsequent cases in many countries
have resulted in increased levels of standardization and quality assurance in forensic
genetics and other areas of forensic science. As a result, the accreditation of both
laboratories and individuals is an increasingly important issue in forensic science.
The combination of technical advances, high levels of standardization and quality
