Arguing the Case for DNA Evidence Based on Probabilistic Genotyping

Thursday September 17th, 2020 // 9:00 am - 12:30 pm

Registration Fee$50.00


This workshop is designed to empower the DNA expert in delivering cogent arguments for DNA evidence based on probabilistic genotyping. With few exceptions, U.S. courts have delivered a number of favorable decisions supporting the admissibility of probabilistic genotyping – though not without potent challenges.

Rather than focusing on ‘how to succeed as an expert witness’, we concentrate on how to draw upon data, logic, case decisions, and scientific literature to present and defend DNA evidence based on probabilistic genotyping. Through interactive strategies, presenters in this workshop will engage participants to outline their own arguments from the information presented.


Learning Outcomes:

  • Small groups will be used to facilitate learning for considering empirical data, the scientific literature and court testimonies to allow the participants to assimilate this information to build highly effective arguments in support of DNA evidence based on probabilistic genotyping.
  • Through review of information related to probabilistic genotyping, participants will recognize unsupported challenges and misrepresentations of probabilistic genotyping software, reflect on hypothetical objections and develop credible counter-arguments.
  • Participants will discuss current topics and methods to address: general acceptance; scientific testing and peer review of the technique; defense access to software and review of source code; error rates; discriminating between donors and non-donors; calibration; variability; mixture ranges, validation and independent testing; and inter-laboratory and inter-software studies; as well as a review of relevant case decisions.


Intended Audience:

Forensic DNA Analysts, Technical Leaders, Lawyers and Judges. An understanding of probabilistic genotyping software would be helpful, but not required.



9:00 – 9:02amWelcome, Introductions, and OverviewMike Coble, Jo Bright
9:02 – 9:15amValidation and Independent TestingJo Bright
9:15 – 9:28amScientific Testing and Peer Review of the TechniqueJo Bright
9:28 – 9:35amQ&AMike Coble, Jo Bright
9:35 – 9:48amGeneral AcceptanceMike Coble
9:48 – 10:01amA Review of the Relevant Case DecisionsMike Coble
10:01 – 10:14amDefense Access to Software and Review of Source CodeMike Coble
10:14 – 10:20amQ&AMike Coble, Jo Bright
10:20 – 10:25amBREAK
10:25 – 10:43amDiscriminating Between Donors and Non-DonorsJo Bright
10:43 – 10:56amMixture RangesJo Bright
10:56 – 11:09amCalibrationJo Bright
11:09 – 11:22amVariabilityJo Bright
11:22 – 11:27amBREAK
11:27 – 11:35amQ&A
11:35 – 11:48amError RatesMike Coble
11:48 – 12:01pmMixture RangesMike Coble
12:01 – 12:14pmInter-laboratory and Inter-software StudiesMike Coble
12:14 – 12:30pmSummary/Final Thoughts/QuestionsMike Coble, Jo Bright


Private: Michael CobleChair

Executive Director, Center for Human Identification, UNTHSC

Michael Coble, PhD, is an Associate Professor and the Executive Director of the Center for Human Identification at the University of North Texas Health Science Center in Fort Worth, Texas. He is a Fellow of the American Academy of Forensic Sciences and a member of the International Society for Forensic Genetics. He serves as a commissioner of the Texas Forensic Science Commission and is an invited guest at the Scientific Working Group on DNA Analysis Methods (SWGDAM).

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Private: Jo-Anne Bright

Environmental Science and Research Limited (ESR) New Zealand

Jo-Anne Bright is a Senior Science Leader within the Forensic Biology group at the Institute of Environmental Science and Research Limited (ESR) New Zealand, where she has worked since 1999. Jo is one of the co developers of STRmix™, expert software for the interpretation of forensic DNA profiles and the new Australasian standard.

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