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Cybergenetics
An Expert System for ScoringDNA Database Profiles
Dr. Mark W. PerlinDr. Mark W. PerlinCybergeneticsCybergeneticsPittsburgh, PAPittsburgh, PA
Cybergenetics
Outline
• • STR Forensic DatabasesSTR Forensic Databases• • The Data Scoring ProblemThe Data Scoring Problem• • An Expert System SolutionAn Expert System Solution• • Complex DNA AnalysisComplex DNA Analysis
Cybergenetics
Generate STR Profiles
STR lengthsSTR lengths
PCR productsPCR products
PCR amplificationPCR amplification
electrophoretic bandselectrophoretic bands
size separationsize separation
data pixelsdata pixels
data acquisitiondata acquisition
• • PCR stutterPCR stutter• • preferential amppreferential amp• • contaminationcontamination
• • peak spreadpeak spread• • lane crosstalklane crosstalk• • size variationsize variation
• • baseline shiftbaseline shift• • dye bleedthroughdye bleedthrough• • size distortionsize distortion
Data artifactsData artifacts
Cybergenetics
Analyze STR Profiles
STR lengthsSTR lengths
PCR productsPCR products
electrophoretic bandselectrophoretic bands
data pixelsdata pixels
designate allelesdesignate alleles
size & quantitatesize & quantitate
recover DNA signalsrecover DNA signals
check allele callscheck allele callsfor PCR errorsfor PCR errors
examine signalsexamine signalsfor separation errorsfor separation errors
inspect datainspect datafor acquisition errorsfor acquisition errors
Human data editingHuman data editingQuality AssuranceQuality Assurance
Cybergenetics
High-Quality STR Data ScoringGenerate STR DataGenerate STR Data
Forensic DNA DatabaseForensic DNA Database
Cybergenetics
Computer Data Scoring
STR lengthsSTR lengths
PCR productsPCR products
electrophoretic bandselectrophoretic bands
data pixelsdata pixels
designate allelesdesignate alleles
size & quantitatesize & quantitate
recover DNA signalsrecover DNA signals
check allele callscheck allele callsfor PCR errorsfor PCR errors
examine signalsexamine signalsfor separation errorsfor separation errors
inspect datainspect datafor acquisition errorsfor acquisition errors
Expert SystemExpert SystemQuality AssuranceQuality Assurance
fast, accurate, objectivefast, accurate, objective
Cybergenetics
TrueAllele™ AutomationFlexible automated analysis:Flexible automated analysis:
DNA fragment sizing and quantitationDNA fragment sizing and quantitation
Any gel or capillary sequencer dataAny gel or capillary sequencer data
image analysissignal analysis
allele assignmentquality assessment
Automated Analysis:• • MacintoshMacintosh• • WindowsWindows• • UNIXUNIX
Focused user review of only the 5%-10% suspect dataFocused user review of only the 5%-10% suspect data
Cybergenetics
Jacob 1• acquire data• process signal• separate colors• remove primers• track sizes• extract profiles
(2) Run Processing & Q/A
Cybergenetics
Jacob 2
• derive allelic ladder• transform coordinates• quantitate trace• call alleles
(3) Allelic Processing & Q/A
Cybergenetics
Quality AssuranceUpdate
Test
Assemblecross-platform
software
AssemblePDF hypertextuser manuals
E-distribution
Cybergenetics
Automated Scoring: FSS/UKGenerate STR DataGenerate STR Data
UK National DNA DatabaseUK National DNA Database
Human reviewsHuman reviewsjust 5%-10%just 5%-10%of the dataof the data
TrueAllele expert systemTrueAllele expert systemscores all STR data and scores all STR data and assesses data qualityassesses data quality
Cybergenetics
NIJ Validation Project
Automatically rescore 30,000 samplesAutomatically rescore 30,000 samples
Florida database Florida database • ABI/310 • ABI/310 • ABI/3700 • ABI/3700Virginia database Virginia database • Hitachi/FMbio2• Hitachi/FMbio2
Compare with CODIS profilesCompare with CODIS profiles
Cybergenetics
Complex DNA Analysis
• • Remove PCR stutterRemove PCR stutter• • Adjust relative amplificationAdjust relative amplification• • Quantitate DNA band overlapQuantitate DNA band overlap
Automatically resolve data artifactsAutomatically resolve data artifacts
Mathematical modelMathematical model
• • Resolve DNA mixturesResolve DNA mixtures