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  • Cybergenetics :: Virginia TrueAllele® Validation Study: Casework Comparison
    i e inconclusive Mathematical computing can overcome these limitations by statistically separating out contributor genotypes from the DNA mixture These genotypes are objectively inferred by thorough consideration of the evidence data and can be compared with reference genotypes to determine match strength This case study examined 111 comparisons from 92 items of evidence in 72 criminal cases involving DNA mixtures For each item a TrueAllele 174 computer 1 provided a DNA match statistic that was reported in a supplemental case report issued by the Virginia DFS laboratory The sensitivity specificity and reproducibility of the computer results were examined Comparison was made to the match information obtained by human review of the same data using Combined Probability of Inclusion CPI or modified CPI mCPI We found TrueAllele computer interpretation to be a reliable method for interpreting DNA mixture evidence Out of 111 DNA match comparisons current mCPI human review could report on 55 of them 49 5 finding an average match statistic of 156 TrueAllele computer interpretation had greater sensitivity providing 102 match statistics 91 9 with an average value of 86 9 billion Thus the computer preserved more of the evidence 91 9 matches by computer versus 49 5 manually as well as the DNA identification information it contained 86 9 billion average match statistic versus 156 manually The computer did not simply add zeros to the DNA match statistic In fact TrueAllele statistics were lower than the corresponding human CPI values in 15 reported items Moreover the computer found no statistical support for a match in some cases While on average TrueAllele does find more matches and computes stronger statistics the system objectively examines DNA evidence without any bias towards the defense or prosecution In addition to increased average sensitivity TrueAllele also maintained excellent specificity The computer can quantify

    Original URL path: http://www.cybgen.com/information/presentations/2013/AAFS/Perlin-Virginia-TrueAllele-validation-study-casework-comparison/page.shtml (2016-02-12)
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  • Cybergenetics :: How Inclusion Interpretation of DNA Mixture Evidence Reduces Identification Information
    measure of DNA identification information calculated as the logarithm of the likelihood ratio LR and measured in ban information units Since CPI can be viewed as a LR this study looked at log LR at individual STR loci to determine how CPI reduces match information We examined 615 locus experiments obtained from 41 inclusions in 31 mixture evidence items that had a reported CPI statistic The items were from 16 cases and included clothing weapons vehicles vaginal swabs and skin swabs Promega PowerPlex 174 16 STR electropherograms were developed on an ABI 3130 174 genetic analyzer and reinterpreted on Cybergenetics TrueAllele 174 genetic calculator There were 517 loci 84 1 of 615 experiments for which both CPI and computer match statistics were calculated At these loci the computer found an average log LR of 0 746 ban per locus forming a bell shaped normal distribution having standard deviation 0 590 DNA evidence need not support an identification hypothesis at every locus as was seen in the 52 10 1 experiments having negative log LR values On these 517 loci CPI yielded an average log LR of 0 489 ban per locus CPI only reports on loci that support an identification and is silent about evidence whose weight does not support an inclusion The CPI weight of evidence values formed a truncated normal distribution These positive log LR numbers had a maximum at 0 ban per locus monotonically decreased to the right with a fitted standard deviation of 0 615 Comparison with the better modeled computer log LR distribution showed that a on average CPI reduces identification information relative to a computer gold standard b CPI discards locus evidence that does not support an inclusion and c CPI can report an inclusion at a locus where the computer finds no support

    Original URL path: http://www.cybgen.com/information/presentations/2013/AAFS/Perlin-How-inclusion-interpretation-of-DNA-mixture-evidence-reduces-identification-information/page.shtml (2016-02-12)
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  • Cybergenetics :: TrueAllele® Challenges in Court and Culture
    Major Projects Newsletters Newsroom Press Releases Trials Contact Directions Information Visiting Support FAQ File Transfer Sending Data Downloads Back to Presentations TrueAllele 174 Challenges in Court and Culture M W Perlin TrueAllele 174 challenges in court and culture 9th Annual

    Original URL path: http://www.cybgen.com/information/presentations/2012/DNATES/Perlin-TrueAllele-challenges-in-court-and-culture/page.shtml (2016-02-12)
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  • Cybergenetics :: TrueAllele® Mixture Interpretation
    Webinars YouTube News Major Projects Newsletters Newsroom Press Releases Trials Contact Directions Information Visiting Support FAQ File Transfer Sending Data Downloads Back to Presentations TrueAllele 174 Mixture Interpretation M W Perlin TrueAllele 174 mixture interpretation 9th Annual DNA Technology Educational

    Original URL path: http://www.cybgen.com/information/presentations/2012/DNATES/Perlin-TrueAllele-mixture-interpretation/page.shtml (2016-02-12)
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  • Cybergenetics :: DNA Mapping the Crime Scene: Do Computers Dream of Electric Peaks?
    persuading a jury But this investigative dream has become a crime laboratory s nightmare Low level touch DNA mixtures stream in through the door along with investigator expectations of fast informative results People and robots churn through challenging evidence cranking out complex EPG signals that defy human interpretation Key DNA is often deemed inconclusive and many comparisons must be made to find a probative match Enter the computer In accordance with SWGDAM DNA interpretation guidelines 1 par 3 2 2 computers can unmix the mixtures separating out the data into each contributor s probabilistic genotype The stochastic uncertainty of low level STR peaks can be reliably modeled through statistical computing 2 Probabilistic genotyping can thoroughly examine the data finding highly informative DNA match statistics Comparing many mixture items with many suspects across multiple cases leads to a very large number of potential matches But perhaps only 10 of these genotype comparisons will actually yield a probative result A computer can map out crime scenes by comparing evidence genotypes with references to implicate suspects With computer assistance a forensic analyst can translate an investigator s dream into evidentiary reality In a recent criminal case a gang was suspected of committing a series of convenience store robberies As the violence escalated resolving these crimes became increasingly important Touch evidence items were collected from five shops yielding a dozen DNA mixtures The STR peak heights were low many under 50 rfu and the mixture complexity was high most items having 3 or 4 contributors Comparisons were needed with ten reference genotypes half suspect and half victim TrueAllele 174 computer interpretation of the touch DNA was able to separate evidence data into probabilistic genotypes Eight of the twelve mixture items matched a reference with DNA statistics ranging from thousands to quintillions Three suspects were

    Original URL path: http://www.cybgen.com/information/presentations/2012/ISHI/Perlin-DNA-mapping-the-crime-scene-do-computers-dream-of-electric-peaks/page.shtml (2016-02-12)
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  • Cybergenetics :: When Good DNA Goes Bad
    Forensic Research Technology 2012 talk Download Handout Download PowerPoint Download Paper Journal of Forensic Research Abstract DNA evidence is the forensic gold standard However the interpretation of this evidence can be challenging Sophisticated mathematical computing can provide accurate and reliable interpretation of DNA mixtures that contain two or more individuals But the reliability of human review of such data is less well established This talk explores what happens when good

    Original URL path: http://www.cybgen.com/information/presentations/2012/ICFRT/Perlin-When-good-DNA-goes-bad/page.shtml (2016-02-12)
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  • Cybergenetics :: Forensic Thinking, Fast and Slow
    News Major Projects Newsletters Newsroom Press Releases Trials Contact Directions Information Visiting Support FAQ File Transfer Sending Data Downloads Back to Presentations Forensic Thinking Fast and Slow M W Perlin Forensic thinking fast and slow International Conference on Forensic Research

    Original URL path: http://www.cybgen.com/information/presentations/2012/ICFRT/Perlin-Forensic-thinking-fast-and-slow/page.shtml (2016-02-12)
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  • Cybergenetics :: The Massereene Touch DNA Evidence
    of touch DNA were deposited on a few items This low level and mixed DNA evidence associated two Republican dissidents Colin Duffy and Brian Shivers with the vehicle or its torching The trial began in November 2011 before Judge Anthony Hart and lasted two months presenting considerable forensic evidence Pittsburgh based Cybergenetics TrueAllele 174 computer system provided DNA match statistics for several of the getaway car evidence items which human

    Original URL path: http://www.cybgen.com/information/presentations/2012/ANZFSS/Perlin-The-Massereene-touch-DNA-evidence/page.shtml (2016-02-12)
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