U.S. flag

An official website of the United States government, Department of Justice.

ASCLD DNA Mixtures Webinar Series: Managers Overview

Event Dates
Event Duration
2 hours

This webinar is targeted to Laboratory Directors and Managers, Quality Mangers, DNA Supervisors and DNA Technical Leaders. There will be a question and answer period after the presentations.

Complex DNA mixtures from more than two individuals and/or profiles amplified with low-level quantities of DNA, can be challenging for the analyst to interpret. Dr. Coble will first provide an overview of the technical issues with mixture interpretation including statistical analyses. Ms. Garcia will then describe the lessons learned in Texas as the state confronts one of the forensic DNA community’s elephants in the room—that DNA mixture interpretation is challenging and laboratories have not always interpreted complex mixtures properly. Ms. Garcia will describe how Texas became aware of the issue, what the Texas Forensic Science Commission did in response and how stakeholders have developed a plan to identify and notify potentially affected defendants in literally tens of thousands of cases. She will discuss what Texas observed regarding the crucial role of SWGDAM and the accrediting bodies, where the gaps in oversight are and what work remains to be done through the OSAC process. Ms. Garcia will make the case for review of DNA mixture cases by any laboratory that may not have applied statistical methods properly (in particular the Combined Probability of Inclusion/Exclusion) and warn against viewing probabilistic genotyping software as a blackbox savior in light of what Texas has already observed for mixture recalculations using the software. Mr. Mills will provide his thoughts on the issues in Texas from a laboratory director’s perspective.

Date Created: December 22, 2016