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  • Cybergenetics :: Objective DNA Mixture Information in the Courtroom: Relevance, Reliability and Acceptance
    people contribute their DNA to a biological sample Data simplifying thresholds fail to give accurate results when applied to complex mixture patterns An entirely objective interpretation approach is to first separate out the genotypes of each mixture contributor without ever seeing the subject and only afterwards make a comparison Comparison of a separated evidence genotype with a subject s reference genotype relative to a population yields a match statistic This

    Original URL path: http://www.cybgen.com/information/publication/2015/NIST/Perlin-Objective-DNA-mixture-information-in-the-courtroom-relevance-reliability-and-acceptance/page.shtml (2016-02-12)
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  • Cybergenetics :: DNA Mapping the Crime Scene: Do Computers Dream of Electric Peaks?

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    Original URL path: /information/publication/2012/ISHI/Perlin-DNA-mapping-the-crime-scene-do-computers-dream-of-electric-peaks/page.shtml (2016-02-12)


  • Cybergenetics :: Combining DNA Evidence for Greater Match Information
    Forensic Science International Genetics Supplement Series DOI 10 1016 j fsigss 2011 09 112 2011 Downloads Download Full Manuscript Full Article Abstract Statistical science studies multiple experiments in order to assess their implications and variation Forensic science is often single experiment and so cannot employ statistical inference With DNA however there can be multiple items and assays from crime scene evidence Since STR data have quantitative peak heights obtained from

    Original URL path: http://www.cybgen.com/information/publication/2011/FSIGSS/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
    Full Article Abstract At the heart of the science of genetics is the genotype a genetic type comprised of allele pairs at a set of loci Since the time of the 19th century genotypes have been understood to be uncertain quantities represented by probability Forensic DNA has uprooted that scientific tradition seeking genotype certainty where none exists in the evidence The result is a tremendous loss of identification information through

    Original URL path: http://www.cybgen.com/information/publication/2011/FSIGSS/Perlin-Investigative-DNA-databases-that-preserve-identification-information/page.shtml (2016-02-12)
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  • Cybergenetics :: Scientific Validation of Mixture Interpretation Method
    been determined and has been communicated by peer review dissemination These Daubert criteria are typically met by conducting scientific validation studies that establish the reliability of an approach by testing it and determining an error rate Forensic STR data have undergone extremely rigorous scientific validation in this country with validation studies of laboratory processes routinely introduced as courtroom evidence in order to establish admissibility Similarly the DNA science of interpreting and matching single source profiles is solidly grounded in the rigor of population genetics Since there is only one correct designation of a pristine single source profile concordance studies can compare the theoretically identical results of two different examiners However interpretation of mixed DNA samples need not produce unambiguous results Different laboratories follow different mixture interpretation guidelines Moreover different examiners within the same laboratory who are following the same guidelines often infer different STR profiles Therefore there is no concordance in current forensic practice on what constitutes a correct mixture solution Thus it is not possible to conduct a mixture interpretation concordance study in order to validate a mixture interpretation method But it is essential to have some way of testing the reliability of mixture interpretation methods so that inferred profiles from DNA mixtures can be scientifically validated and admitted as legal evidence We have developed a general approach to scientifically validating mixed DNA profiles Instead of conducting a concordance comparison which is not possible our approach determines the amount of information present in the DNA match between an inferred mixture profile and a reference profile By examining these numerical measures of match information one can assess the reliability of a mixture interpretation method We have tested our validation approach on mixed DNA samples from multiple crime laboratories each of whom uses their own interpretation methods We found that different

    Original URL path: http://www.cybgen.com/information/publication/2006/ISHI/Perlin-Scientific-validation-of-mixture-interpretation-method/page.shtml (2016-02-12)
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  • Cybergenetics :: Real-time DNA Investigation
    led policing approach can reduce crime by removing active criminals from society before they can commit more crimes DNA laboratory automation has introduced robotic batch processing that can transform biological specimens into informative data in less than a day However the task of human data review interpretation matching and reporting often takes months To complete DNA investigations within 48 hours it would be useful to have a computer system that can perform these information processing tasks and deliver investigative leads within several hours Cybergenetics TrueAllele 174 System 3 is an automated computer based system that interprets DNA evidence into profiles matches these profiles against other profiles and delivers profile and match results to end users via Internet The system can be distributed across multiple locations with DNA interpretation match and reporting occurring simultaneously for different cases on different computers that share a coordinating database Doubling the number of interpretation computers halves the processing time Once a case s DNA peak information has been uploaded to the TrueAllele database all downstream processing can proceed automatically without human intervention We have been scientifically assessing TrueAllele System 3 in several real time DNA investigative applications Useful measures for comparing the computer against current manual systems include speed accuracy capacity information labor and cost For property crimes we have looked at the system s interpretation match and reporting of crime scene samples against an offender database As reported previously at the 2003 Promega Symposium the mixture analysis functionality can rapidly infer profiles from unknown suspect sexual assault data these DNA profiles are highly informative relative to human review and can be automatically matched against offender databases We have also applied the system to the World Trade Center WTC mass disaster where the problem has analogous elements of inferring crime scene profiles from the victim

    Original URL path: http://www.cybgen.com/information/publication/2005/ISHI/Perlin-Real-time-DNA-investigation/page.shtml (2016-02-12)
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  • Cybergenetics :: Simple Reporting of Complex DNA Evidence: Automated Computer Interpretation
    can present the results of its rigorous deliberations as ordinary probabilities that are understandable to juries This paper describes the collaborative study design data generation analytic interpretation and scientific results obtained in validating our expert system The validation study was designed collaboratively with crime labs in Florida Maryland and Virginia The mock rape kit approach analyzed a set of two contributor sperm fraction DNA mixtures 10 30 50 70 and 90 proportions at 1 0 0 5 0 25 and 0 125 ng dilutions along with their victim reference samples NIST prepared the mixed DNA stock solutions in known proportions for two individual pairs and sent these materials to the ten participating forensic laboratories Each lab followed detailed study protocols generated PCR data for 56 templates and sent their original sequencer data to Cybergenetics for automated computer interpretation In addition each lab also provided about 100 single source samples that were used for calibrating their PCR process and artifacts stutter preferential amplification peak variation etc All STR chemistries and DNA sequencers in current forensic use were represented Cybergenetics ran their sequencer independent TrueAllele 174 program on the original lab data to generate a database of quality checked quantitated peaks under five minutes of human time per gel The interpretation expert system was then applied to these data no human time The calibration produced graphs of stutter and pref amp for each marker The automated mixture analysis for each lab s 40 unknown suspect cases mixture and reference data but no suspect data yielded an estimate of the mixing proportion the genotype confidence set at each locus and quantitative bar graphs that permitted rapid visual comparison between the observed data and the best genotype model These computer results were reviewed by each laboratory The DNA templates and the computer interpretation were

    Original URL path: http://www.cybgen.com/information/publication/2003/ISHI/Perlin-Simple-reporting-of-complex-DNA-evidence-automated-computer-interpretation/page.shtml (2016-02-12)
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  • Cybergenetics :: Automated STR Data Analysis: Validation Studies
    is not extracted from the data despite considerable examiner effort We are rapidly developing novel computational mathematical and statistical methods that help overcome these limitations This report focuses on the collaborative validation of these methods Convicted offender DNA databases must be accurate To minimize error the original STR data are carefully reviewed by two or more people Moreover in a troubleshooting capacity this review helps to continuously maintain high quality lab data But there are not enough skilled personnel for this arduous repetitive task To alleviate this critical labor shortage we developed the TrueAllele 174 expert system The computer program automates virtually every human review function and provides consistent quality assessment and allele designation The TrueAllele validation began with the original data from 50 000 CODIS genotypes System parameters were adapted to the instruments ABI 310 ABI 3700 Hitachi FMbio and panels ProfilerPlus Cofiler PowerPlex 1 2 used to generate the data Computer processing was then done with automated scoring of the high quality data followed by limited human review The computed expert system results were compared against manually scored results We report here on the relative accuracy and efficiency of the automated approach In casework DNA mixtures are analyzed to assess candidate suspects When inferred profiles are matched against a convicted offender database useful leads are generated When matched against a known suspect the mixture data can help convict or exonerate However data uncertainty leads to inherently complex and ambiguous analysis We have developed a new technology Linear Mixture Analysis LMA which uses multilocus quantitative data to automatically eliminate this complexity LMA objectively resolves mixtures into candidate profiles and provides highly informative statistical measures The LMA validation involves both synthetic mixtures and actual casework profiles derived from diverse panels and instruments After quantitative peak analysis using TrueAllele on the

    Original URL path: http://www.cybgen.com/information/publication/2001/ISHI/Perlin-Ban-Automated-STR-data-analysis-validation-studies/page.shtml (2016-02-12)
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