The Tuesday opening keynote at ISHI 37 examines two forensic DNA cases in which evidence types long considered limited for traditional analysis were evaluated using advanced sequencing and computational approaches — and what the analytical strategies behind those results mean for the field.
Some evidence types have historically sat at the edge of what forensic DNA analysis could reliably address — not because the science was absent, but because the methods available at the time weren’t sufficient to meet evidentiary standards. Advanced sequencing and computational approaches are changing that, and the courtroom record is beginning to reflect it.
The Tuesday opening keynote at ISHI 37 examines two of those cases — and the analytical strategies, quality control frameworks, and evidentiary foundations behind them.
Case One: Identical Twins and Ultra-Deep Sequencing
The Russell Marubbio case out of Virginia produced what is believed to be the first U.S. conviction in which ultra-deep whole-genome sequencing was used to differentiate identical twins — previously considered genetically indistinguishable in forensic analysis.
The approach targeted rare somatic mutations: post-zygotic DNA changes that accumulate independently in each twin over time. Identifying those variants required sequencing depth beyond standard forensic protocols and a quality control framework sufficient to support the evidentiary weight the case required.
The session will examine the analytical strategy, the quality control framework, and the evidentiary foundation that supported its acceptance in court.
Case Two: Whole-Genome Sequencing From a Rootless Hair Shaft
The Anne Pham cold case out of California was resolved using whole-genome sequencing from a single rootless hair shaft — evidence long considered unsuitable for nuclear DNA analysis. Modern sequencing technologies made it possible to recover genome-wide data from the degraded shaft material, enabling SNP-based identification in the absence of a CODIS profile.
The session will address the contamination safeguards, validation studies, and conservative interpretation frameworks applied when working with limited biological material.
What Attendees Will Take Back
Across both cases, the session is designed to give attendees a grounded framework for evaluating when advanced methods are appropriate — and how to apply and communicate them with rigor. Intended takeaways include:
- How to think differently about degraded or legacy evidence
- Decision frameworks for determining when advanced methods may be appropriate
- The role of the forensic scientist as an impartial expert
- Effective strategies for communicating new technologies
The Speakers
Dr. Janet Cady is a Senior Bioinformatics Scientist at Parabon NanoLabs. She holds a PhD in Human and Statistical Genetics from Washington University in St. Louis and has performed advanced DNA analysis on hundreds of forensic cases since joining Parabon in 2016. Her work specializes in method development and the analysis of sequencing data. She will present on the Marubbio identical twins case.
Dr. Cristina Valencia is Laboratory Director at Astrea Forensics. She holds a PhD in Anthropology, with a technical focus in paleogenomics and forensic anthropological analysis. She will present on the Anne Pham case and the whole-genome sequencing approach applied to rootless hair shaft evidence.