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

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

DNA Typing: Useful Tool to Solve Crimes or Invasion of Privacy?

DNA in a test tubeThis year marks the tenth anniversary of the complete human genome sequence. The Human Genome Project revealed a surprising fact: Only 1% of our genome encodes proteins. This equates to a paltry 20,000–25,000 genes. The function of the other 99% of our DNA remained a mystery. Shortly after the sequencing was completed, the National Human Genome Research Institute (NHGRI) launched a new research project, termed the Encyclopedia Of DNA Elements (ENCODE), to identify DNA elements and try to find a purpose for the other 99% of our DNA. This project has contributed greatly to our understanding of the human genome, as documented in the 30 ENCODE-related papers published in Nature, Genome Research and Genome Biology in 2012 (see the Nature web site. However, the ENCODE project is being used in an unforeseen way: to support an appeal to the recent US Supreme Court decision about the constitutionality of collection and analysis of DNA from arrestees.

Continue reading

DNA Typing Confirms Bronze Age Mix-and-Match Burials

Archaeologists have made an interesting discovery while excavating the late Bronze Age/early Iron Age settlement named Cladh Hallan on the island of South Uist in the Outer Hebrides, Scotland. They have uncovered four human skeletons buried at regular intervals beneath three roundhouses dating from the 11th century BC: an adult male, an adult female, a 10–14-year-old girl and a 3-year-old child. The careful arrangement of these burials directly below the roundhouses led archaeologists to initially hypothesize that these might be foundation burials—an ancient practice in which people, usually younger people, were sacrificed and buried under a building’s foundation in the belief that their blood and spirit would protect and strengthen the building and building site. As strange as that custom seems to us, it gets weirder. Two of these skeletons showed signs of mummification and contained skeletal elements from multiple individuals intentionally pieced together to form intact skeletons. Continue reading

Not My Shade of DNA

LipstickDNA testing is providing some answers in a nine-month campaign of hate and revenge involving two British women: a wife and her husband’s mistress. Between May of 2010 and February of 2011, the wife was stabbed in the stomach with a screwdriver, had bleach thrown in her face, received death threats in the mail, been the victim of an arson attack and had a threatening message written on her apartment window in lipstick. She blamed the mistress in her reports to police. As a result, the mistress had been arrested numerous times and spent 20 hours in police custody despite her assertions that she was not involved in any of the attacks. The situation became so maddening that her family started a diary of her whereabouts to help prove her innocence.

Hoping to find some physical evidence that might shed some light on the events, police examined the evidence in the case more closely. This included DNA analysis of the lipstick used to write the threatening message and saliva used to seal the envelope containing the death threats. The results of the DNA analysis were shocking. Continue reading

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

How to Catch a Serial Killer

A Lear jet“[I]deas about who killed whom does not come to the criminal profiler in flashes of insight, nor does a group of FBI profilers fly around the country in a Lear jet and solve heinous murders within a few days with the help of a computer genius back in Quantico who seemingly has unlimited resources and who admittedly conducts illegal hacking into data banks that are highly confidential.”

This excerpt from a recent Forensic Science International paper (1) pokes fun at criminal profiling as portrayed on television shows such as Criminal Minds. However, this is just another example of Hollywood producers embellishing reality and stretching the truth to try to increase the entertainment value. [To learn about how the television show CSI has warped public perception of the forensic sciences, check out The Reality of Crime Scene Investigation. Part I: Common Myths].

So, if these Criminal Minds and CSI approaches to catching murderers aren’t accurate, how do law enforcement officers identify killers and bring them to justice? Continue reading

Justice 27 Years Too Late: The William Dillon Story

Balance of justiceWilliam (Bill) Dillon spent more than half of his life in a prison for a crime he did not commit. Now, after being exonerated by DNA testing, he is telling his story of injustice and, eventually, freedom. On Wednesday, January 12, he visited Promega Corporation in Madison, Wisconsin, to relate his story and his efforts as an advocate for exonerees who are released from prison with little support from the same justice system that failed them in the first place.

The events that lead to Dillon’s false imprisonment started on August 17, 1981, when a man was found beaten to death in the parking area of a beach in a Florida tourist town. On August 22, detectives were investigating the crime scene, when Dillon and his brother drove into the parking area. Little did Dillon know that his decision to drive to the beach that day would lead to a wrongful conviction and 27 years and 8 months in prison.

Continue reading

The Blood of Louis XVI

GuillotineThis post was chosen as an Editor's Selection for ResearchBlogging.orgA bloody handkerchief stored in an ornately decorated gourd seems like a gruesome keepsake, but that is exactly what scientists are using to obtain the presumptive genetic profile of King Louis XVI of France.

“Who would want such an odd souvenir?” you might ask. Well, apparently a bloody handkerchief was a perfectly acceptable memento from the French Revolution. It represented the power of the common person in the new republic of France.

Let me explain: In 1774, Louis XVI inherited the French throne and, with it, enormous responsibilities: The government was deeply in debt, and French citizens were impoverished and heavily taxed. Louis XVI and his financial ministers made a series of poor decisions, and by 1788, France was nearly bankrupt and Louis was very unpopular with his subjects. Continue reading