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An Approach to De-convolution of Mixtures in Touch DNA Samples. Download now!

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7th QIAGEN Investigator Forum - Lisbon, March 8, 2018 . An Approach to De-convolution of Mixtures in Touch DNA Samples. Presenter: Lisa Dierig, Institute of Legal Medicine, Ulm

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An Approach to De-convolution of Mixtures in Touch DNA Samples. Download now!

  1. 1. An Approach to De-convolution of Mixtures inTouch DNA Samples Lisa Dierig, Institute of Legal Medicine, Ulm 7th Qiagen Investigator Forum, Lisbon, March 8, 2018
  2. 2. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 2 Touch DNA „Every contact leaves a trace“ Dr. Edmond Locard • Minute amounts of (degraded) DNA • Admixed profiles • Unbalanced peaks • Stochastic effects http://clipart.coolclips.com/480/vectors/tf05156/CoolClips_vc007427.png
  3. 3. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 3 Touch DNA • Case scenario: Physical assault • „Blind swabbing“ • Collection of single (skin) bioparticles Aim: Prevention of admixed profiles and improving DNA quantity http://www.hollowaylawgroup.com/public /uploads/cms/151008072833_icon11.png
  4. 4. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 4 Mock case scenario
  5. 5. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 5 Sample collection Adhesive film
  6. 6. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 6 Microscopic examination 1 mm Microscope https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTw7ftVr7FQxT73fG48PXCjT2SjqDTw-z3SmyE7L8bMfEgSSkXr
  7. 7. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 7 Downstream analysis • 5% Chelex + Proteinase K • qPCR (Quantiplex® Pro) • Low-Template PCR (ESSplex SE QS) • ABI 3130, POP7 Lysis (Chelex) Quantification Low-template PCR CE http://www.hsc.edu.kw/RCF/Images/ABI3130.jpg https://www.qiagen.com/us/shop/detection-solutions/human-identity/investigator-essplex-se-qs-kit/#orderinginformation
  8. 8. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 8 Staining of bioparticles
  9. 9. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 9 Staining of bioparticles before after 1 mm
  10. 10. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 10 Staining of bioparticles Pro • Time saving • Greater visibility → mainly smaller cells before after 1 mm
  11. 11. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 11 Staining of bioparticles Pro • Time saving • Greater visibility → mainly smaller cells Contra • Toxic reagent • Risk of contamination before after 1 mm
  12. 12. Collection of cells on adhesive film Single skin cells/clumps selection Swabbing of small areas An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon Optimization of cell collection method Increasing DNA quantity without generating admixed profiles 12
  13. 13. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 13 Optimization of collection method Single cells (n=206) Areas (n=156) negative 74% 3% < 1 pg/μl 22% 71% 1-2 pg/μl 2% 15% >2 pg/μl 2% 11% Outliers >6 pg/μl not shown Increase of DNA quantity
  14. 14. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 14 Optimization of collection method n=5 n=22 n=18
  15. 15. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 15 Optimization of collection method 13 database entries possible Profiles (n=41) Major offender 35 Major victim 2 Inconclusive 4 > 1 pg/µl partial profiles > 2 pg/µl database entry possible
  16. 16. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 16 Summary • Improvement of visibility oMicroscopic technique oStaining with trypan blue • New collection and analysis method oLess mixtures than expected oIdentification of offender oFrom 1 pg/µl partial profiles → from 2 pg/µl database entry possible oCaution: artifacts!
  17. 17. An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 17 Future prospects • Varying scenarios oAdditional victim/offender combinations oSame-sex mixtures oMixtures with 2+ donors oSkin-skin contact oDifferent items • Narrowing down the swabbing area
  18. 18. Thank you for your attention! An approach to de-convolution of mixtures in touch DNA samples | Lisa Dierig | Institute of Legal Medicine, Ulm | March 8, 2018, Lisbon 18 Lisa Dierig Institute of Legal Medicine University Hospital Ulm Albert-Einstein-Allee 23 89081 Ulm, Germany E-mail: lisa.dierig@uniklinik-ulm.de Phone: +49 731 500 65033

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