Promega Tech Tour 2016: Preview of a Fascinating DNA Crime Story

“Is your life just like CSI?”

That is the prevailing question I’m asked when someone learns of my occupation as Deputy Sheriff Criminalist for the Contra Costa County (CA) Office of the Sheriff. Alas, my life is not quite so glamorous. It actually often entails entering formulas into an excel spreadsheet while being placed on hold as I order some pipette tips.

But, why does it have to be that way?

crime sceneI have attended my fair share of professional conferences and workshops and written numerous journal articles. As a forensic scientist I do believe in the importance of sharing data, new techniques, and new methodologies with my colleagues. Yet what I think is not highlighted enough is the one element that differentiates our field from any other scientific field—our involvement with the criminal justice system.  Every case we work on involves a mystery, a crime, a victim(s), and a suspect(s).  And while scientists in other fields typically only speak to other scientists, in my world, forensic scientists usually interact with a person in a black robe who has the power to strongly influence the outcome of a case.  These wildly frustrating, invigorating, and challenging cases are the most interesting things about our field, and yet we hardly share our stories.

I aim to change that.

I have been fortunate enough to be invited to speak at the 2016 Promega Tech Tour on April 12 at the CA Department of Justice Jan Bashinski DNA Laboratory in Richmond, CA.  The story I plan to share is about the small part I played in the case against Joseph Naso, the serial killer who preyed upon his victims from the 1950’s through the 1990’s in California. Continue reading “Promega Tech Tour 2016: Preview of a Fascinating DNA Crime Story”

A Social Media Perspective of AAFS 2016

The American Academy of Forensic Sciences’ 68th annual conference took place in Las Vegas February 22–27th, and those of you who did not attend, like me, had to live vicariously through the social media posts of those who did. The question on everyone’s mind: Who was up five hundy by midnight?

Vegas-baby-Vegas

Okay, okay, most people who went to AAFS went for scientific purposes, and in fact, @andycyim was the only one to post a tribute to Swingers with a #vegasbaby tweet. Tip of the hat to you, Andy. So what did the Twitterverse look like during the week of the conference? I analyzed nearly 600 tweets and found some interesting patterns of how scientists interact on social media during a conference. More on my methodology is at the end of this article.

Continue reading “A Social Media Perspective of AAFS 2016”

Mitochondrial DNA Typing in Forensics

23540687_lMitochondria, often thought of as powerhouses of the cell, are fascinating eukaryotic organelles with a double-layered membrane and their own genome. Mitochondrial DNA (Mt DNA) is typically about 16570 bases, circular, highly compact, haploid and contains 37 genes, all of which are essential for normal mitochondrial function. Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation, a process that uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell’s main energy currency. The remaining genes code for transfer RNA (tRNA) and ribosomal RNA (rRNA) which are necessary for translating messenger RNA transcribed from nuclear DNA, into protein molecules.

One of the most important characteristics of mitochondrial genome that is relevant to field of forensics is the copy number. Continue reading “Mitochondrial DNA Typing in Forensics”

The Power and Potential of Next-Generation Sequencing

DNA in a test tubeNext-generation sequencing (NGS), also known as massively parallel sequencing, is revolutionizing genomic research. NGS technologies have made whole genome sequencing fast and easy, leading to dramatic advances in evolutionary biology and phylogenetics, personalized medicine and forensic science. Why is NGS such a hot topic right now?

Continue reading “The Power and Potential of Next-Generation Sequencing”

A Molecular Approach to Estimating Time of Death

Stopwatch
I will admit that over the years, I have watched various crime scene investigation shows and read several books by Kathy Reichs and Patricia Cornwell because I was fascinated by forensic science. These same books and shows are a guilty pleasure because as a scientist, I know these portrayals do not accurately reflect how laboratory work is done. Answers are not so cut and dried as an exact estimation of time of death—for example, death was five hours before the body was found in an abandoned warehouse. However, scientists are always looking for ways to improve accuracy in time of death estimates, which are currently based on a few physical clues that are affected by environment and other factors. One approach taken by Sampaio-Silva et al. (1) was to assess the RNA degradation using reverse transcription quantitative PCR (RT-qPCR).

The authors of this PLOS ONE article wanted to determine if nucleic acid degradation could be used as a method to improve time of death estimates. Continue reading “A Molecular Approach to Estimating Time of Death”

Join the Fun! Learn About Cutting-Edge Forensic Science. Attend ISHI.

International Symposium on Human Identification logo
Join me in Washington, D.C., for the 22nd ISHI.

Well, I just booked my plane tickets to Washington, DC., to attend the 22nd International Symposium on Human Identification (ISHI), which is being held October 3–6. I am excited because every year ISHI is filled with great presentations and posters that represent the newest advances in forensic science. Plus, I have opportunities to interact with some of the greatest minds in the field. These opportunities include more formal interactions, such as asking questions of presenters during the general session and poster sessions and “talking shop” during the breaks, lunches and evening events, but also informal interactions like chatting between mouthfuls of Texas barbecue (16th and 21st ISHI), line dancing (17th ISHI in Nashville, Tennessee), sipping Pinot Noir at a Hollywood hotspot (18th and 19th ISHI) and having pictures taken with a fairly convincing Elvis impersonator (20th ISHI in Las Vegas, Nevada).

What are the hot topics that will have attendees buzzing this year?

Continue reading “Join the Fun! Learn About Cutting-Edge Forensic Science. Attend ISHI.”

DNA: Giving Voice to a New Population of Victims

She’s only two years old, but her face is a mass of deep cuts. Her left ear is torn almost completely off. Her right leg was broken a while back. It never healed right, and bends at an unnatural angle. She doesn’t put weight on it. There are puncture wounds on her neck. Her name might be Daisy, or Lola, or Chance. She’s a pitbull used for dog fighting. And she’s just one of countless victims of this illegal underground blood sport that is staged for the purposes of entertainment, gambling, status jockeying and sometimes just pure cruelty by what an ASPCA estimate puts at tens of thousands of people across the United States.

Up until recently, the canine victims of this crime were largely voiceless. They lived with injury and pain. They charged into fights fueled by both instinct and the desire to please the very master who sent them into harm’s way for a few hundred bucks or an uptick in personal status. Most ultimately died, some mercifully via a bullet, others slowly and painfully, abandoned after losing a fight. But now, these victims have a small but very powerful ally: DNA. Continue reading “DNA: Giving Voice to a New Population of Victims”