In 2022, one laboratory’s journey from traditional forensic DNA testing methods to next generation sequencing (NGS) was explored. In 2023, that journey concluded with the first successful admissibility hearing of NGS data in the United States. Identity SNP, aSTR and Y-STR DNA profiles obtained from the evidence collected from the crime scene samples of the double homicide were presented at the hearing and expert testimony was heard exploring the evolution of DNA testing, laying the scientific foundation for NGS technology, and addressing the applications of sequencing data for identification.
Laboratories considering implementing new technology, whether it be NGS or another advanced technology, are faced with a multitude of decisions, often making the task seem overwhelming. In her presentation at ISHI 35, Mandi aims to address key components of the transition strategy including implementation considerations, case and sample selection for testing, expert witness selection criteria, and comprehensive trial preparation encompassing discovery materials and evidentiary presentation. A detailed case review will look further into how NGS was utilized in trial for the conviction of subject Adrian Chavez.
Can you give us a sneak peek into the main theme of your presentation and why it’s important for our audience?
My presentation will take an in depth look at the first criminal case to go to trial and complete an admissibility hearing in the United States using next generation sequencing. We will review the case details, trial preparation, expert witness selection, presentation strategies and recommendations to others for future admissibility hearings.
What inspired you to explore the topic of your presentation?
I was the lead analyst on this project as the DNA Technical Leader from validation to implementation and training to the final expert testimony. I believe NGS is a game changer for the forensic DNA field and am passionate about helping others bring this into their laboratories.
What’s one common misconception about your area of expertise you’d like to clarify?
One common misconception I believe is that people only consider NGS technology if they are interested in forensic genetic genealogy (FGG) and they are missing the benefits for regular casework that NGS brings to the table. Our plan for this project never involved bringing FGG inhouse; we selected NGS for the increase in data per sample, sensitivity of the testing kit, and improved ability to estimate the number of contributors in a complex mixture with the identification of isoalleles.
How do you hope your presentation will impact the audience or industry?
Part of implementing any new technology is presenting it in court in an admissibility hearing. If this has not been done yet in your state or anywhere in the US, this can obviously cause several to hold off on validating the technology. I am hopeful that through my journey I can answer questions and ease any fears or concerns surrounding making the leap from CE to NGS.
When you’re not working, what’s your favorite way to unwind or relax?
In my “free time” I actively train in Brazilian jiu-jitsu and kickboxing along side my three children and compete regularly. We also love camping and riding ATVs any free weekend we can get out of town.
What’s the best piece of advice you’ve ever received?
Someone told me once “remember Mandi the plane takes off against the wind not with it.” At the time I didn’t really understand or digest this quote. Over the years though, personally and professionally, I have been challenged, it has been hard, I have felt like everything and everyone is fighting against me but I remember this quote and continue to push forward focused on my vision and goals. You can reach any height and achieve any goal if you never give up and just keep pushing through little by little.
If you could only eat one dish for the rest of your life, what would it be?
TACOS!
What were you doing in 1989, when ISHI first started?
In 1989 I was 6 years old so probably in 1st grade, playing with toys, tormenting my 2 older brothers and living my best life!
Can you share a memorable moment from ISHI that has stayed with you?
Every ISHI experience is memorable. The connections made are priceless. It is the one week I look forward to every year, a chance to be surrounded by field experts I have looked up to in my career, friendships I have made through this career and new analysts I hopefully get to mentor through my work.
