M4 Flashcards
1
Q
4 bases projecting from the backbone of DNA that consists 5 Carbon Sugars (ribose) and phosphates that form the backbone of DNA
A
A - adenine G- guanine, T - thymine, C - cytosine
2
Q
DNA is a polymer consisting of monomer units known as
A
nucleotides
3
Q
Nucleotides consist of an organic base consisting of
A
A 5 carbon sugar (ribose) and phosphate to form the backbone of DNA.
4
Q
DNA regulates cell activity by
A
specifying how to make proteins
5
Q
Some proteins are structural and others function as
A
enzymes
6
Q
Genetic differences among people that enable them to be distinguished are called
A
Genetic Polymorphisms
7
Q
Prior to DNA typing analysis, forensic scientists used
A
proteins and enzymes as genetic markers to try to individualize biological evidence
8
Q
The entire complement/entire set of DNA in one cell is called the
A
genome
9
Q
Human DNA has ~3.5 Billion
A
base pairs (bp)
10
Q
The base sequence in the coding portions of the DNA is known as the
A
genetic code
11
Q
The majority of DNA is
A
Non-CODING
12
Q
Non-Coding DNA regions contain
A
Tandemly Repeated Sequences (STR)
13
Q
DNA Human Identity Testing is used in
A
Forensic cases - Matching suspect w/evidence
Paternity testing - Identifying Father
Historical investigations
Missing persons investigations
Mass disasters - putting pieces back together
Military DNA “dog tag”
Convicted felon DNA
Emigration & Human Trafficking
14
Q
The DNA Profiling Process involves
A
DNA Extraction
DNA Quantitation
PCR Amplification
Separation & Detection
Interpretation
15
Q
Steps in Nucleic Acid Extraction
A
- Cell & Tissue Disruption
- Lysis of cellular & organelle membranes
- Removal of protein & cytoplasmic constituents
16
Q
Cell & Tissue Disruption
A
a method in which the outer boundary or cell membrane is broken down in order to release cellular materials such as DNA
17
Q
Used in the process of of nucleic acid extraction to break down the protein component of the cell membrane and allow access to the DNA & RNA
A
Proteinase K
18
Q
Mechanical methods of cell & tissue disruption
A
Grind bones & teeth
Decalcification with Ethylenediaminetetraacetic acid (EDTA)
19
Q
Lysis of Cellular & Organelle Membranes
A
Release DNA from nuclei & mitochondria
20
Q
Lysis
A
the disintegration of a cell by rupture of the cell wall or membrane
21
Q
Lysis buffer
A
buffer solution used for the purpose of breaking open cells for use in molecular biology
22
Q
Lysis buffer consists of
A
- Detergents (SDS) - destroys membranes
- Buffer (Tris) - maintain pH, avoid enzyme degradation by Dnase
- High salt concentrations (guanidinium salts) - Dissociate histones from DNA
- Reducing agents (DTT) - Inhibit oxidation that can damage DNA
- Chelating agents - capture divalent metal ions that are Dnase cofactors
23
Q
Histones
A
a protein that provides structural support for a chromosome
24
Q
Cytoplasmic components & proteins interfere with
A
DNA isolation & need to be removed from the sample in DNA extraction
25
Methods to remove dissolved proteins
Phenol-chloroform-isoamyl mixtures
DNA binding to a solid matrix - wash away contaminants
26
Methods of Extraction in the
3. Removal of Protein & Cytoplasmic Constituents
a) Solid phase-based (Silica) Extraction
b) Differential Lysis Extraction
c) Application of Automation & Robotic platforms
27
Removal of Protein & Cytoplasmic Constituents Method based on Sample Type as appropriate for the laboratory
1 Selection of suitable isolation method for sample type & condition
2. Pre-extraction cell separation (e.g., cell sorting, laser capture microdissection)
3. Pre-extraction processing (e.g., soak grinding, demineralization)
4. Post-extraction processing (e.g., filtration, concentration, preservation conditions)
5. Non-extraction direct amplification approaches
28
3 Removal of Protein & Cytoplasmic
a) Silica-based Extraction
* DNA is reversibly absorbed by silica in the presence of chaotropic salts
* Chaotropic salts disrupt hydrogen bonds
- causes nucleic acids to
become hydrophobic
- Phosphate groups available
to interact w/silica
29
Silica
is the stationary phase to which DNA binds
30
Removal of Protein & Cytoplasmic Constituents
DNA Absorption onto Silica
* Occurs in the presence of chaotropic agents
* Double-stranded DNA is absorbed
* Cellular contaminants DO NOT BIND
31
Removal of Protein & Cytoplasmic Constituents
Washing
* Removes chaotropic salts & contaminants
* Certain solvents (EtOH) will not affect DNA's interaction with silica
32
Removal of Protein & Cytoplasmic Constituents
Elution of DNA
DNA is eluted by rehydration w/low salt solutions
33
Elution of DNA
generally a process of extracting one material from another by washing with a solvent
34
3. Removal of Protein & Cytoplasmic Constituents Steps
1. Cell Lysis & Protein Digestion
2. DNA Absorption onto Silica
3. Washing
4. Elution of DNA
35
Removal of Protein & Cytoplasmic Constituents
c) Differential Extraction
THE GOAL of the procedure is to separate a sample that would otherwise generate a mixed DNA profile into 2 separate DNA profiles by enriching for the DNA from the MALE sperm donor (e.g., collected in a sexual assault case) in the sperm fraction and enriching for the DNA from the donor of the non-sperm cell fraction.
36
In Differential Extraction sperm and non-sperm cells are lysed at separate times based on
the properties of the different cell membranes. Sperm and non-sperm cell fraction can be isolated.
37
In Differential Extraction is useful for extracting DNA in
Sexual assault cases
* usually mixtures of spermatozoa from MALES & epithelial cells from FEMALES
* mixed DNA profiles complicate data interpretation
38
In Differential Extraction lyse non-sperm cells with
Proteinase K
* Sperm cells are resistant
---Membranes contain proteins crosslinked by disulfide bonds
39
Differential Extraction Method includes
* Centrifuge tube
* Lyse sperm cells with Proteinase K & DTT
40
Dithiothreitol (DTT)
is a reducing agent that breaks down the protein disulphide bridges that make up the sperm nuclear membrane.
41
Sperm nuclei are impervious to digestion without
DTT
42
In Differential Extraction Method 1 sample generates
2 fractions of DNA
* Sperm & non-sperm cell DNA may not be completely separated
43
3. Removal of Protein & Cytoplasmic Constituents
c) Automation & Robotic Platforms
QIAcube connect or classic QIAcube
44
DNA Advisory Board (DAB) requires this standard of Human-Specific DNA quantitation
Standard 9.4 of Human-Specific DNA quantitation so the appropriate levels of human DNA can be included in the subsequent PCR amplification.
45
Multiplex STR typing works best with a
fairly narrow range of human DNA - typically .5 to 2.0 ng of input DNA works best with commercial STR kits.
46
DNA Quantification
determines the amount of HUMAN DNA in a sample
47
Polymerase Chain Reaction (PCR)
a laboratory technique for rapidly producing (amplifying) millions to billions of copies of a specific segment of DNA
48
A narrow concentration range is required to
"SEED" the PCR reaction of amplification
49
Too much or too little DNA gives rise to
artifacts - false positive or false negative alleles
50
DNA Quantification Test should measure
quality as well as quantity of DNA
51
Quantitating DNA is important for forensics because
* If we can confidently determine the amount of DNA in an extract we can then ask:
- Will mitochondrial sequence be required?
- Should we use low copy number LCN methods of STRs?
- Re-extract the sample?
52
If problems occur in the STR typing process we can have confidence that the
DNA template is not the source (CE, cycler, kit)
53
3 Common Quantitation Methods
1. Slot Blot Assay
2. Interchelating Dye
3. Quantitative PCR
54
Slot Blot Method
* Detects primate DNA
* Genomic DNA is denatured & small volume is spotted onto a nitrocellulose
* DNA immobilized on a nylon membrane
* Hybridization w/labeled 40 - nucleotide probe
55
Denatured DNA
When DNA is made single stranded and the single stranded denatured DNA links to the nitrocellulose membrane
56
Interchetaling Dye Method
* Fluorescent Dye used
* Not specific to HUMAN DNA
* Fluorescence measure by spectrofluorometer
57
Quantitative PCR (qPCR or "real time PCR")
* Method of choice in most crime labs
* More sensitive
* Large range of detection
* Amount of PCR product amplified during exponential phase of PCR correlates w/the initial concentration
* Real-time PCR most common method in forensic lab
* analyzes the amplification of a target sequence at each cycle of PCR
58
DNA replication begins w/the
unwinding of the DNA strands of the double helix
59
In DNA replication each strand is now exposed to a collection of free nucleotides that will be used to
recreate the double helix, letter by letter using base pairing.
60
PCR is the outgrowth of knowledge gained from understanding of how
DNA strands naturally replicate within a cell.
61
For the forensic scientists, PCR offers a distinct advantage in that it can amplify
minute quantities of DNA many millions of times
62
PCR Phases
Exponential Phase
Linear Phase
Plateau ("end point")
63
Amount of PCR product amplified during exponential phase of PCR correlates with the
initial concentration
64
PCR Results produce
* the standard curve from the known standards
* Quantities from unknown samples
* Quantitation data used to know how much goes into the next step in the profiling process -- STR amplification
.5 to 2 ng is the ideal amount
* typically aim to use 1 ng
65
Advantages to using Real Time qPCR
* The availability of commercial qPCR kits
* Higher throughput & reduced user intervention
* amenable to automation
* High sensitivity
* Large dynamic range: ~30 pg to ~ 30 ng
* More accurate measurements of small quantities of DNA
* Assays are target specific & can be multiplexed
66
Real Time qPCR Challenges
* Subject to inhibition
* Quantitation precision suffers at low copy numbers
* when working below 100 pg qPCR is still subject to variability & uncertainty
* qPCR quantities specific target sequences, it does not quantify "DNA"
67
Autosomal Short Tandem Repeats (STR) method requires
(Multiplex) <1ng of DNA to type of 20 STR loci
68
Polymerase Chain Reaction (PCR) method
* Molecular Xeroxing
* An enzymatic process by which a specific region of DNA is replicated during repetitive cycles and GOAL is to generate MANY COPIEs for analysis
* 3 Temperature phases replicate or "amplify" the desired DNA fragment(s)
69
Copies of DNA generated in the PCR process are called
products or amplicons
70
Steps in the PCR/Thermal Cycling
1. The DNA is HEATED to separate it (denaturation)
2. PRIMERs are added, which hybridize w/strands (annealing).
3. DNA polymerase & free nucleotides are added to rebuild each of the separated strands (extension).
4. Now, this cycle is repeated 25 to 30 times
71
Primers
short strands of DNA used to target specific regions of DNA for replication
72
Each strand of DNA is used a TEMPLATE to create a REPLICATE that permits DOUBLING of the number of target molecule w/
Each cycle of HEATING & COOLING
73
Heating & Cooling samples in a precise thermal cycling pattern
over ~30 cycles & during each cycle, a copy of the target DNA sequence is generated for every molecule containing the target sequence
74
Steps in the PCR/ Thermal Cycling
Using Multiplex PCR
* Specific regions of the human genome are simultaneously targeted w/SEQUENCE-SPECIFIC oligonucleotide PCR primers
*Copied w/DNA polymerase & doxynucleotide triphophate building blocks.
75
In a matter of a few hours how many copies of the genome of each SPECIFIC REGION
Close to a billion
76
The PCR amplification process incorporates
Fluorescently-labeled primers into the PCR products that enable multi-color fluorescence detection.
77
PCR Amplification is based on
quantification results; 1ng of DNA is taken to be amplified
78
Advantages of PCR amplification w/FORENSIC specimens
* very small amounts of template required
* Effective w/degraded DNA
* Specific DNA sequences can be amplified simultaneously - multiplexing
* HUMAN specific primers used - NO contaminant DNA
79
Advantages of STR Kits
* Quality control of materials is in the hands of the manufacture
* Improves consistency in results across laboratories -- SAME ALLELIC ladders used
* Common LOCI & PCR conditions used
* Simpler for the user obtain results
80
Disadvantages of STR Kits
* Contents may NOT be completely known to user
* Higher cost to obtain results
81
13 STR loci (plus Amelogenin) were initially chosen for analysis as they provided
a high level of individualization; also for ALL forensic laboratories contribute profiles of the same genetic markers to the DNA database.
82
January 1, 2017, 20 Core CODIS STR Loci are required because
1. facilitates greater discrimination
2. assists in missing person investigations
3. encourages international data sharing efforts by having more LOCI in common w/other countries for comparison
83
Inhibitors of STR kits
* interact w/DNA template (polymerase) causing amplification to FAIL- can be detected using an internal positive controll
* MUST be REMOVED during extraction
84
Inhibitors can be detected
using an internal positive control
85
Common inhibitors in forensic samples
* Heme from blood
* Indigo dye from fabric
* Melanin in hair samples
86
Contamination of STR kits
PCR is very sensitive
* Pre & post PCR sample should be processed in separate areas or at DIFFERENT time
* Reagents for pre & post PCR should be separated
* Protective gear such as gloves, lab coats, facial masks, & hair caps
* Aerosol-resistant pipet tips
* DNA - free solutions & test tubes
* Controls must be used to detect contamination
* DNA profiles of lab members should be available for comparison - Staff ELIMINATION database
87
Electrophoresis
* technique that separates DNA amplification products based on SIZE and ELECTRICAL CHARGE
* Phosphate groups on the background of the DNA molecule, readily give up their H+ IONS, leaving DNA molecules negatively charged
88
Fluorescent Detection
* amplification products have a fluorescent "label" attached to the primer
* Label is seen through excitation via a laser & corresponding emission captured w/a camera
89
Capillary Electrophoresis
Multiplex PCR produces 20 or more different sized DNA fragments representing ...
different ALLELES that must be RESOLVED from each other.
90
Capillary Electrophoresis
*Single based resolution is required to distinguished between...
closely spaced alleles (e.g., THO1 alleles 9.3 & 10)
91
Capillary Electrophoresis (CE)
*a SEPARATION step is required to pull...
DIFFERENT sized fragments apart.
92
Under electrical field, DNA will migrate...
AWAY from negative electrode (cathode), & move TOWARD the positive (anode).
93
ABI (Applied Biosystems 3100 Genetic Analyzer is the
Most commonly used CE systems
94
CE instruments electrokinetically inject the negatively charged DNA molecules from a
formamide-diluted sample of the PCR products mixed w/an internal size standard
95
CE - The size standard is labeled w/a separate fluorescent dye to enable calibration of each analysis so that comparisons can be made between...
samples run at different times on the same instrument.
96
CE - A polymer solution (sieve) inside the capillary permits resolution of DNA fragments differing by as little as a
a single base pair (bp) over a size range of approximately 100 to 400 bp
97
CE - Formamide
denaturant solution that disrupts the hydrogen bonds between the complementary strands of the PCR products
*helps keep the strands denatured
98
CE - Polymer
linear flexible chains act as obstacles to be navigated by the larger negatively charged DNA fragments
* Larger molecules are slowed down more than the smaller more agile DNA fragments, thus separating them
99
CE - Fluorescent dyes are present on one strand of each PCR product due to incorporation of a
PCR primer during multiplex PCR amplification.
* These dyes are excited by laser as they pass a detection point in the CE instrument
100
CE - 4, 5, or 6 fluorescent dyes used in STR analysis have
different chemical properties
* they emit light at slightly different chemical properties, they emit light at slightly different wavelengths enabling detection in different color channels.
101
Requirements for ACCURATE STR Typing
1. High precision
2. Color separation of different dye sets used
3. Resolution of at least 2 bp > 300 bp
4. Reliable sizing over 75-450 bp region
102
Advantages of CE
1. The injection, separation, & detection steps can be fully automated
2. Multiple samples can be run unattended by CE
3. Tiny quantities of sample are consumed w/an injection
4. Samples can easily be retested if needed w/o more preparation
103
Disadvantage of CE
1. Single capillary instruments CANNOT process high numbers of samples compared the gels.
2. A high start-up cost
3. Maintenance & supplies for the instruments can be expensive
104
Allelic Ladder
is an artificial mixture of the ALL common alleles present in the human population for a particular STR marker
*the analysis software use these known peaks to determine the genotype of the unknown samples.
105
Allele Calls
Comparison of the unknown fragments to the migration pattern of the allelic ladder allows determination of the genotype.
*software programs use macros to automatically make the comparison
106
Discrimination power through Multiplexing
The loci used in STR systems have been shown to be inherited independently, which provides powerful statistical weight to genotypes.
107
Thresholds
are set to separate signal from noise - are we are confident the peak is real?
108
Signal peak height
is measured in relative fluorescence units (RFUs) that are related to the amount of DNA present in the sample loaded onto the analysis instrument
109
Detection Threshold for Measuring DNA data
* These thresholds for reliable data are determined through Validation Studies
* typically vary from 50 RFU to 200 RFU
110
Detection (analytical) Threshold
* Dependent on instrument sensitivity
*Impacted by instrument baseline noise
111
Dropout (stochastic) Threshold
* occurs when an allele is not copied during the PCR amplification process.
*Dependent on biological sensitivity
* Important in mixture interpretation
112
DNA Data Analysis
* The analyst carefully reviews the DNA data & checks software genotype calls & edits out artifacts
* Software designates sample genotypes via comparison to the allelic ladder
113
Determining the Genotypes of STR Fragments
* Genotype for an STR locus is the number of repeat units of the allele
* Genotype is determined by using the allelic ladder
114
STR Results
* Individuals will differ from one another in terms of their STR profile
* STR genotype can then be put into a alpha numeric form for search on a DNA database
115
Off-ladder allele
a rare allele that fails to match alleles in the ladder
116
3 Types of "Off-Ladder" Alleles
1. Below Ladder
2. Above Ladder
3. "Variant" between Ladder Alleles
117
# of Steps Involved in STR Genotyping
1. Data Collection
2. Color Separators
3. Peak Identification
4. Peak Sizing
5. Comparison to Allelic Ladder
6. Genotype Assignment to Alleles
7. Data Review by Scientist
8. Confirmation by second Scientist
118
Biological Artifacts
a) Stuttering/Stutter
b) Non-Template Addition
c) Heterozygote Imbalance
d) Allelic Dropout
119
Electrophoretic Artifacts
a) Pull up Peaks
b) Spikes
120
Stuttering - Amplification Artifacts
* Peaks that show up primarily 1 repeat less than the rule allele as a result of strand SLIPPAGE during DNA synthesis (PCR amplification)
* Stutter peaks make mixture analysis MORE DIFFICULT
121
Short repeat unit loci are
MORE likely to stutter
121
Loci w/complex repeat sequences
have LESS stutter
122
Proposed mechanisms for stutter products
* During the DNA synthesis step of PCR amplification, a DNA polymerase slips
* a region of the primer-template complex becomes unpaired, causing the template strand to form a loop
* The result of the loop is a SHORTENED PCR product smaller than the template by a single repeat unit.
123
Non-Template Adenylation
*Taq polymerase will often add an extra nucleotide to the end of a PCR product -- usually and "A" (adenylation)
* DNA adds adenosine
*Multiplex STR kits use conditions that favor adenylation
124
Heterozygote
Two alleles are different
125
Heterozygote imbalance
* 1 heterozygote allele has a larger peak than the other allele
as a result of preferential amplification or mutations leading amplification fail
126
Pull-up Peaks
* Minor peak of 1 color on an electrophergram is pulled up from a major allelic peak in another color, when colors have overlapping spectra & can happen when a sample is OVERLOADED
127
Spikes
* Sharp peaks w/similar signal intensities that are present in all color panels of an electropherogram that is caused by air bubbles or urea crystals in the capillary, or voltage spikes
128
SOFTGENETICS
* STR Analysis Software
* Compatible w/all commercial STR typing kits
* GeneMaker HID superior to GeneMapper
*Used in 28 countries
129
STR Interpretation Software
Contamination Check
* Allows data to be reviewed for possible contamination
* Profile to profile comparison w/in a project
* Comparison to lab's elimination database
130
STR Interpretation Software
Mixture Assessment
* Attempts to determine an individual contributor to a mixture based on user's pre-defined criteria
* The software will calculate the probability of each genotypic combination based on the STR results
131
In Mixture Assessment the resulting probabilities yield a possible contributor to the mixture along w/combined probability of
inclusion/exclusion (PI/PE), random man not excluded (RMNE), & a likelihood ratio (LR) when identifying a known contributor.
132
Degraded DNA
* Environmental exposure of biological evidence
* UV light, humidity, high temps, bacterial contamination
* Older methods of DNA Typing made it impossible to analyze
* PCR amplification allows for detecting miniscule amounts of DNA
133
Degradation can reduce the height of some peaks or
make them disappear entirely
134
135
Allelic dropout
partial DNA profile
136
DNA Repair
* PreCR Repair Mix
* Recover damaged, compromised, or degraded DNA samples
* Repair DNA prior to its use in DNA-related technologies
* Easy-to-use
* Does not harm DNA template
137
Mixtures
Samples of DNA w/2 or more contributors
* Often encountered in forensic cases in which evidence recovered from the victim is mixed w/a suspect's bodily fluids
138
3 main factors determine the complexity of a mixture
1. How many people contributed DNA to the mixture?
2. How much DND did each person contribute?
3. How degraded is the DNA?
139
Drop-Outs
Degraded, or inhibited DNA & results i n partial DNA profiles, where the DNA from 1 or more contributors is NOT present at all loci.
140
Drop-Ins
is the presence of low amounts of DNA w/in a profile that are not inherent to the DNA extract.
141
Random Match Probability (RMP)
estimates the probability of a matching DNA profile (not the person of interest's) w/in chosen population.
142
Likelihood Ratio (LR)
is NOT a probability but rather a RATIO of 2 probabilities that evaluates the evidence given 2 or more mutually exclusive propositions:
LR = Pr(EIH1)/Pr(EIH2)
*E is the evidence - DNA profiles
H1 is the proposition that the POI is the contributor of DNA
H2 is the proposition the some other randomly selected individual from the population unrelated to the POI
143
Combined Probability of Inclusion (CPI) or Random Man Not Excluded (RMNE)
* Is the simplest method
* Not an interpretation method
* It is used to ESTIMATE the proportion of unrelated individuals in the population that could be included as possible contributors to the profile
* Can be OVERLY INCLUSIVE - dealing w/low-level mixture data
144
Steps in analyzing Mixtures
1. Determine the genotypes of ALL alleles & identify the number of contributors
2. Estimate rations of the contributors
3. Compare reference samples
145
Steps in Mixture INTERPRETATION
1. Identify the Presence of a Mixture
2. Designate Allele Peaks
3. Identify the number of Potential Contributors
4. Estimate the Relative Ratio of the Individuals Contributing to the Mixture
5. Consider ALL Possible Genotype Combinations
6. Compare Reference Samples
146
The Key in Mixtures is to ask the right questions:
1. How complex is the mixture in terms of number of contributors & the amount of DNA from each?
2. How confident can we be that the DNA is relevant to the case?
3. What other types of evidence exist to corroborate the DNA evidence?
147
Interpretation of STR Profiling Results
* Inclusion - Match
* Exclusion
* Inconclusive Result
148
CORE STR Markers -
Loci should NOT be linked or inherited together
* Forensic STR loci are usually on different chromosomes to be sure they are not linked
** Loci that are far apart on the same chromosome may be used
* Have few amplification artifacts such as stutter
149
FBI & NIST raising standard of STR loci from 13 to 20
* Quality Assurance Standards
* Makes international DNA searches more effective
* Better for degraded samples
* If 7 markers are dropped out, you still have what is considered a full profile in 2-16
150
With the NEW 20 CORE STR Markers the chances that 2 people who are not closely related have the same number of repeats at both copies of all 20 markers is
LESS than 1 in a billion billion
151
Database
is an organized file or files of data that can be searched to retrieve information
152
DNA Databases
compare profiles derived from evidentiary samples to a database of DNA profiles obtained from known individuals to provide law enforcement w/investigative leads
153
CODIS
enables federal, state, and local crime labs to exchange & compare DNA profiles electronically.
* Consists of NDIS, SDIS, & LDIS
154
Categories of forensic/offender DNA records may be stored & searched in NDIS:
Accordance w/the Federal DNA Act
* Arrestee
* Convicted Offender
* Detainee
* Forensic Mixture
* Forensic Partial
* Forensic Unknown
* Juvenile
* Legal
* Multi-allelic Offender
155
3 Criteria for determining the eligibility of a DNA record
1. That a crime has been committed
2. That demonstrates the DNA sample was recovered directly from the crime scene & is attributed to the putative
3. The elimination sample(s) have been requested, if applicable
156
Missing Person Index
* Unidentified Human Remains
* Missing persons direct reference samples
* Family reference samples
157
Only the following information is stored & can be searched at the national level:
1. The DNA profile
2. The Agency Identifier of the agency submitting the DNA profile
3. The Specimen Identification Number
4. The DNA laboratory personnel associated w/a DNA profile analysis
158
158
Requirements for the DNA data submitted to the NDIS:
1. DNA data must be in accordance w/FBI director's Quality Assurance Standards
2. DNA data must be generated by an accredited lab
3. Accredited lab undergoes External Audit every 2 years
4. Must be 1 of the Categories of data acceptable at NDIS
5. Must meet minimum CODIS core Loci requirements
6. PCR data must be generated using PCR accepted kits
7. Laboratories must have & follow expungement procedures
159
Searching CODIS -
High Stringency
is a search that requires all alleles to match between the 2 DNA profiles
160
Forensic Partial & Forensic Mixture Indices
Where DNA profiles that are partial of mixtures are maintained
161
CODIS Searching -
Moderate Stringency
a search that requires all alleles to match, but the 2 DNA profiles can contain a different number or alleles
162
Partial Matches as defined by FBI
between 2 single source profiles have at each locus all of the alleles of 1 sample represented in the other sample
** NOT an EXACT MATCH of 2 profiles
163
Sex & Red Blood cells are the only cells that do not have
a complete copy of your DNA
164
