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  • Cybergenetics :: Reanimating Zombie™ DNA
    Projects Newsletters Newsroom Press Releases Trials Contact Directions Information Visiting Support FAQ File Transfer Sending Data Downloads Back to Presentations Reanimating Zombie DNA M W Perlin Reanimating Zombie DNA Penn State Dickinson Law School State College PA 21 Sep 2012

    Original URL path: http://www.cybgen.com/information/presentations/2012/PSU_law/Perlin-Reanimating-Zombie-DNA/page.shtml (2016-02-12)
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  • Cybergenetics :: Combining DNA Evidence for Greater Match Information
    elicit maximal information from an experimental design The statistical mechanism is the joint likelihood function DNA evidence is often challenging to interpret When a DNA sample has low quantities is degraded or contains several individuals mixed together no single allele pair may be able to explain the STR data Multiple allele pair possibilities then become feasible with an associated loss of identification information It can then become important to use all the available experiment data in order to restore information In forensic DNA science human data interpretation is usually performed on data derived from just one item This practice is a natural consequence of thresholds applying a preset peak height level to quantitative peak height data in order to simplify human data interpretation which creates artificial all or none qualitative allele possibilities However the resulting genetic profiles cannot be mathematically combined Some groups may heuristically combine profiles after data interpretation to form a consensus profile but this practice has little statistical justification Quantitative computer interpretation of continuous electrophoretic STR data signals however has no such artificial limitation It is therefore natural to mathematically preserve identification information by inferring a genotype using a joint likelihood function that examines all the independent data simultaneously A likelihood function mathematically quantifies how well alternative hypotheses explain a fixed data result A joint likelihood function assesses these hypotheses on multiple data items simultaneously Typically the data are drawn from independent experiments Therefore the joint likelihood simply multiplies together the likelihood numbers from separate experiments jointly conditioned on a common explanatory hypothesis This talk describes the joint interpretation of DNA evidence We show how likelihood functions can be used to rigorously explain DNA evidence and how joint likelihood functions can combine evidence We present results that show how the number of assumed contributors affect the inferred

    Original URL path: http://www.cybgen.com/information/presentations/2012/AAFS/Perlin-Combining-DNA-evidence-for-greater-match-information/page.shtml (2016-02-12)
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  • Cybergenetics :: Investigative DNA Databases that Preserve Identification Information
    databases like CODIS can become far more sensitive and specific This sharpened information capability makes DNA databases more successful in connecting the right criminal to DNA mixture evidence A DNA database can link crime scenes to suspects providing investigative leads These DNA associations can solve cold cases track terrorists and stop criminals before they inflict further harm However current government databases do not fully preserve DNA identification information and cannot maximize public safety DNA data is summarized in a genotype The genotype can be stored on a database and compared with other genotypes to form a likelihood ratio LR match statistic Data uncertainty present in most evidence particularly DNA mixtures translates into genotype probability Highly informative DNA mixture interpretation uses all the quantitative data placing higher probability on more likely genotype values Most evidence though is currently interpreted by a qualitative human review that diffuses probability across infeasible solutions Since the LR is proportional to the true genotype probability weaker interpretation methods lead to weaker or nonexistent DNA matches The weakest DNA mixture interpretation method is the Combined Probability of Inclusion CPI also known as Random Man Not Excluded RMNE CPI uses thresholds to truncate quantitative data into all or none qualitative allele events The current DNA databases including CODIS use a CPI allele representation that discards considerable genotype information losing sensitivity and specificity The probabilistic genotype representation described by SWGDAM is part of the new ANSI NIST ITL data exchange standard Unlike allele lists a probability representation can preserve all DNA evidence identification information on a forensic database and calculate accurate LR statistics as it matches across the database ISFG s 2006 mixture guidelines recommend the more informative LR over CPI Unfortunately current databases transform hard won LR genotypes into less informative CPI alleles This talk shows how genotype

    Original URL path: http://www.cybgen.com/information/presentations/2012/AAFS/Perlin-Investigative-DNA-databases-that-preserve-identification-information/page.shtml (2016-02-12)
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  • Cybergenetics :: Touch DNA and the Massereene Barracks attack investigation
    was ruptured on the night of March 7 2009 when two hooded gunmen emerged from a car outside the Massereene Barracks with assault rifles In the first attack on British soldiers in over ten years the assailants fired more than 60 rounds at unarmed soldiers and civilians killing Sappers Mark Quinsey and Patrick Azimkar who were collecting a Domino s pizza delivery The Real IRA paramilitary organization claimed responsibility for the attack The action was universally denounced by all parties in Northern Ireland and actually strengthened the peace process The abandoned getaway car was burned to destroy personally identifying evidence but trace amounts of touch DNA were left 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 Their nonjury Belfast trial began in November 2011 before Judge Anthony Hart and lasted two months presenting considerable forensic evidence witnesses do not testify in such cases Pittsburgh based Cybergenetics TrueAllele 174 computer system provided DNA match statistics for several of the getaway car evidence items which human review could not After three days of expert testimony and cross examination Judge Hart admitted the computer interpretation

    Original URL path: http://www.cybgen.com/information/presentations/2012/Allegheny_County_CLE/Perlin_Galloway_Touch_DNA_and_the_Massereene_Barracks_attack_investigation/page.shtml (2016-02-12)
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  • Cybergenetics :: Creating Informative DNA Libraries Using Computer Reinterpretation of Existing Data
    data However current DNA interpretation guidelines can limit the amount of information that they are permitted to report As more challenging data e g mixed low level degraded enters the laboratory workflow we see scientists working ever harder to extract diminishing identification information Computer interpretation using probabilistic genotypes is now allowed under the SWGDAM guidelines Section 3 2 2 The computer can use validated quantitative models instead of qualitative thresholds to interpret and match the DNA evidence Therefore a computer assistant enables an analyst to extract all the information present in their data In projects with two separate labs Cybergenetics used the TrueAllele computer technology to re interpret existing DNA evidence data Probabilistic genotypes provided higher match statistics of use to prosecutors whereas human interpretation based on 2010 SWGDAM guidelines often produced no match information at all TrueAllele computer interpretation preserves on average a million times more identification information as measured by DNA match statistics One DNA laboratory was in a large state while the other was in a small county Cybergenetics processed about 150 highly complex cases over a period of 4 months for the large state These cases routinely included 3 and 4 person mixtures often with low amounts or degraded DNA Cybergenetics processed the DNA case data in large batches as they arrived creating a library of computer interpreted DNA evidence Once the results were needed for court Cybergenetics would then further examine the results and prepare case reports which the lab would forward on to law enforcement agencies The computer inferred match statistics were generally appreciably larger than the human interpretation results TrueAllele DNA interpretation has been successfully introduced as evidence in state and federal courts The TrueAllele match results have led to convictions and plea bargains it has also excluded suspects from DNA evidence Cybergenetics

    Original URL path: http://www.cybgen.com/information/presentations/2011/NEAFS/David-Creating-informative-DNA-libraries-using-computer-reinterpretation-of-existing-data/page.shtml (2016-02-12)
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  • Cybergenetics :: Exploring the capabilities of mixture interpretation using TrueAllele software
    Austria 3 Sep 2011 Talk Slide presentation of Michael Coble s International Society for Forensic Genetics 2011 talk Download Presentation Abstract DNA mixtures from sexual assault evidence or high volume crimes such as burglaries can be challenging for the forensic scientist to interpret The problem is exacerbated when the evidence contains more than two contributors or is highly compromised due to DNA degradation ISFG guidelines for mixture interpretation developed by Gill et al 2006 have been widely accepted by the global forensic DNA community Laboratories have developed in house spreadsheets or have purchased commercial software to rapidly calculate the multiple parameters necessary for mixture interpretation using the Clayton et al 1998 method e g peak height ratio mixture ratio etc Additionally mixture software can be used to calculate statistics using either Random Man Not Excluded e g combined probability of inclusion CPI or Combined Likelihood Ratio CLR to evaluate the data We have explored the capabilities of the TrueAllele software Cybergenetics Pittsburgh PA USA by analyzing an assortment of two three and four person mixtures The software uses quantitative probabilistic genotype modeling of the data to form a joint LR statistic for the weight of the evidence We examined a

    Original URL path: http://www.cybgen.com/information/presentations/2011/ISFG/Coble-Exploring-the-capabilities-of-mixture-interpretation-using-TrueAllele-software/page.shtml (2016-02-12)
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  • Cybergenetics :: DNA Mixture Deconvolution by Binomial Sampling of Individual Cells
    Support FAQ File Transfer Sending Data Downloads Back to Presentations DNA Mixture Deconvolution by Binomial Sampling of Individual Cells J Ballantyne and M W Perlin DNA mixture deconvolution by binomial sampling of individual cells International Conference on Forensic Inference and Statistics Seattle WA 20 Jul 2011 Talk PowerPoint presentation with live audio recording of Dr Jack Ballantyne and Dr Mark Perlin s talk at the International Conference on Forensic Inference

    Original URL path: http://www.cybgen.com/information/presentations/2011/ICFIS/Ballantyne_Perlin_DNA_mixture_deconvolution_by_binomial_sampling_of_individual_cells/page.shtml (2016-02-12)
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  • Cybergenetics :: New York State Commission on Forensic Science
    Newsroom Press Releases Trials Contact Directions Information Visiting Support FAQ File Transfer Sending Data Downloads Back to Presentations New York State Commission on Forensic Science New York State Division of Criminal Justice Services Commission on Forensic Science Meeting New York NY 27 Jun 2011 Abstract On June 27 2011 the New York State Commission on Forensic Science approved the use of TrueAllele technology for forensic casework Talks Video recordings of

    Original URL path: http://www.cybgen.com/information/presentations/2011/NYSCFS/Commission/page.shtml (2016-02-12)
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