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The DNA Analysis Unit
I analyzes body fluids and body fluid stains recovered as evidence
in violent crimes. Examinations include the identification and
characterization of blood, semen, saliva, and other body fluids
using traditional serological techniques and related biochemical
analysis. Once the stain is identified, it is characterized by
DNA analysis using the restriction fragment length polymorphism
(RFLP) and/or polymerase chain reaction (PCR) techniques. The
results of the analyses are compared to results obtained from
known blood and/or saliva samples submitted from the victims
DNA examinations involve the analysis of biological evidence
found on clothing and other substrates.
In 1996 the DNA Analysis
Unit II began using mitochondrial DNA (mtDNA) analysis, which
is applied to evidence containing small or degraded quantities
of DNA from hair, bones, teeth, and body fluids. The results
of mtDNA analysis are compared to blood and/or saliva submitted
from the victims and/or suspects. The Unit examines evidence
that may not have been suitable for significant comparison purposes
prior to the development of this technique.
The Mitochondrial DNA
Population Database is composed of complete nucleotide sequences
of the first and second hypervariable segments of the control
region of the human mitochondrial genome and consists of two
main datasets. The first dataset contains individuals from populations
of forensic relevance and is contributed mostly by the Scientific
Working Group on DNA Analysis Methods and forensic laboratories.
The second dataset, based on mtDNA concordance, contains nucleotide
sequences from ethnic groups around the world.
Mitochondrial DNA analysis
Both datasets are bundled
in MitoSearch, a software package specifically designed for the
compilation and analysis of mtDNA databases. MitoSearch estimates
the relative frequency of specific sequences for the various
populations represented within the database and assesses the
relative relatedness of each population with reference to the
size of each database.