NGS in DNA Forensics: Benefits, Challenges, and Future Potential

Kaitlin Searfoss:
Hi everyone, welcome to this podcast from Cambridge Health Tech Institute for the NGS for DNA Forensics Symposia taking place August 18th as part of the next generation DX Summit I'm Kaitlin Searfoss, conference producer.

We have with us today one of our speakers, Doctor Cassandra Calloway, an assistant scientist, DNA program coordinator, and assistant adjunct professor at the Children's Hospital Oakland Research Institute in the universities of California at Davis and San Francisco. Thanks for joining us today, Doctor Calloway.

Cassandra Calloway:
Thank you.

Kaitlin Searfoss:
You're speaking at the NGS for DNA Forensics symposium on your recently developed probe capture essay for sequencing of highly degraded and limited DNA samples. Can you tell us a little bit about how using massively parallel sequencing or next generation sequencing for this work is different from traditional methods?

Cassandra Calloway:
Recently we have developed a probe capture next generation sequencing method for analysis of the entire mitochondrial genome as well as nuclear markers, and this allows us for the analysis of the most challenging forensic samples, and that would include highly degraded samples, limited as well as mixtures. And the probe capture method can allow us to capture and sequence very highly fragmented DNA samples and does not require intact priming sites like traditional PCR methods. Next generation sequencing technologies, because of the clonal sequencing aspect of the technology can allow us also for analyzing mixed samples and resolution of mixtures for forensics is certainly an important aspect of the technology that can allow us to analyze these more challenging samples.

Also, the technology allows us to look at many different types of markers all in one run. So we won't now be limited just to analyzing our short pattern repeats separately from our snip markers, we can do that all together because of these new technologies allow us to sequence many different markers all in one run.

Kaitlin Searfoss:
How do you see NGS moving into the field of forensics? What are some of the benefits and disadvantages you foresee?

Cassandra Calloway:
I would see it first being used for the most challenging samples, and specifically in mitochondrial DNA. Some of the current limitations currently for [singer 00:02:11] sequencing as you can't really resolve mixtures, and again because of the clonal sequencing aspect of massively parallel sequencing, these technologies can now allow that. And, as I also mentioned the pro-capture that we're developing can allow for analysis for highly fragmented samples, and so that will open the door to analysis of samples that we couldn't analyze before. I think overall, the field of forensics could move towards using next generation sequencing first for these more challenging samples, but overall in the future, I think we can apply it to any of the types of samples.

I would say some of the disadvantages would be the large data that is generated. We need to figure out better ways to store it, but also for data analysis, and then moving into creating more databases for these types of markers.

I would say another benefit overall for next generation sequencing and forensics is it allows us to look at many different types of markers together, and some of the other technologies, the traditional methods have been limiting for those. So, now we can analyze mitochondrial DNA and nuclear markers together in one ASA compared to what we had to do before where they had to be separate. So, I would see moving forward these new technologies to allow us to analyze the many types of markers in one run, compared to what we are typically doing and we have to make more difficult choices.

Kaitlin Searfoss:
What are you most interested in learning about it? The Next Generation Diagnostic Summit?

Cassandra Calloway:
For me, it's certainly a networking opportunity, and since my work stands both forensics and clinical genetics, it'll be a great opportunity for me to see the various aspects of next generation sequencing and how it's being applied to both the forensics as well as clinical applications. And I'm very excited to share that the forensic session is taking place, and I'll be interested in also attending the MIPT, or the non-invasive pre-natal testing session.

Kaitlin Searfoss:
Thanks so much for your time today Dr. Calloway. That was Dr. Cassandra Calloway who is an assistant scientist, DNA program coordinator, and assistant adjunct professor at the Children's Hospital Oakland Research Institute, and the Universities of California at Davis and San Francisco. She'll be speaking at the DNA Forensics Symposium on August 18th at the Next Generation DX Summit. I'm Kaitlin Searfoss. Thank you for listening.