Revolutionising DNA analysis in major crime investigations ?· Cybergenetics © 2007-2014 1 Revolutionising…

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<ul><li><p>Cybergenetics 2007-2014 1 </p><p>Revolutionising DNA analysis in major crime investigations </p><p>The Investigator Conferences Green Park Conference Centre </p><p>May, 2014 Aylesbury, Buckinghamshire </p><p>Mark W Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA </p><p>Cybergenetics 2003-2014 </p><p>Commonwealth v. Lyons homicide: DNA mixture evidence </p><p>Victim's blood spatter pulsating spray from </p><p>severed carotid artery </p><p>75% victim 25% other </p></li><li><p>Cybergenetics 2007-2014 2 </p><p>DNA molecule </p><p>Copy DNA </p><p>Copy intact DNA </p><p>Normal DNA signal </p></li><li><p>Cybergenetics 2007-2014 3 </p><p>Degraded DNA </p><p>Cant copy broken DNA </p><p>Longer molecules copy less With degradation, a longer DNA molecule has a greater chance of having a break </p><p>DNA decay curve </p><p>DNA size </p><p>Obs</p><p>erve</p><p>d D</p><p>NA </p><p>With degradation, a longer DNA molecule makes fewer DNA copies </p></li><li><p>Cybergenetics 2007-2014 4 </p><p>Degraded DNA signal </p><p>Degraded DNA Mixture </p><p>Degraded other DNA </p><p>Victim DNA </p><p>Match statistic comparison </p><p>Human Computer </p><p>42,000 9,500,000,000,000 </p></li><li><p>Cybergenetics 2007-2014 5 </p><p>Computer Interpretation of Quantitative DNA Evidence </p><p>Commonwealth v. Lyons June, 2011 </p><p>Reading, PA </p><p>Mark W Perlin, PhD, MD, PhD Cybergenetics, Pittsburgh, PA </p><p>Cybergenetics 2003-2011 </p><p>DNA evidence interpretation Evidence </p><p>item Evidence </p><p>data Lab Infer </p><p>10 11 12 </p><p>Evidence genotype </p><p>Known genotype </p><p>10, 12 @ 50% 11, 12 @ 30% 12, 12 @ 20% </p><p>10, 12 </p><p>Compare </p><p>Computers can use all the data Quantitative peak heights at locus D8S1179 </p><p>victim </p><p>other </p></li><li><p>Cybergenetics 2007-2014 6 </p><p>People may use less of the data </p><p>Over threshold, peaks become allele events. </p><p>Under threshold, alleles vanish. </p><p>All-or-none allele peaks; ignore victim genotype </p><p>Threshold </p><p>How the computer thinks Consider every possible genotype solution </p><p>victim other </p><p>Explain the peak pattern Better explanation </p><p>gives a higher probability </p><p>Evidence genotypes victim other </p></li><li><p>Cybergenetics 2007-2014 7 </p><p>DNA match information </p><p>Probability(evidence match) Probability(coincidental match) </p><p>How much more does the suspect match the evidence than a random person? </p><p>6x </p><p>Is the suspect in the evidence? A match between the suspect and the evidence </p><p>is 9.46 trillion times more probable than coincidence. </p><p>Yes, with a reasonable degree of scientific certainty, evidence item Q9 contains DNA </p><p>from the genotype of suspect item K2. </p><p>Is the victim in the evidence? A match between the victim and the evidence </p><p>is 1.27 quintillion times more probable than coincidence. </p><p>Yes, with a reasonable degree of scientific certainty, evidence item Q9 contains DNA </p><p>from the genotype of victim item K1. </p></li><li><p>Cybergenetics 2007-2014 8 </p><p>Getting Started http://www.cybgen.com/support </p><p>Questions? </p></li></ul>

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