Criminalistics, Seattle, Coffee, and Science — They All Matter


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Source:  Noelle J. Umback, PhD, Section Program Co-Chair

The theme of the 2018 AAFS meeting is Science Matters. The general public often believes that when something scientific is reported, it has become fact. However, we know that change is at the heart of the Scientific Method. Experimentation may answer some questions about a particular biological process, but it inevitably leads to more questions. This is patently clear today in the field of Forensic DNA Analysis. Once (and still, most likely) considered the Gold Standard of forensic endeavors, our field has experienced a lot of changes over the past few years — philosophical as well as technical.

As technical developments are adopted and analytical methods become more sensitive, we are continually able to obtain more genetic information from evidence than what was previously possible. However, this increase in sensitivity represents a significant challenge, as it leads to a need for more sophisticated interpretations. By looking at a laboratory report issued ten or more years ago, the nature of this evolution becomes readily apparent. In accordance with the nature of science, change and adaptation are inevitable in our field.

The initial phase of DNA testing in the form of Restriction Fragment Length Polymorphism (RFLP) testing had highly discriminatory capabilities but was restricted to large amounts of high-quality DNA (i.e., blood and semen). The second (and current) phase of DNA testing in the form of Short Tandem Repeat (STR) profiling was initially less discriminatory but was capable of extracting extensive genotypic information from the often-degraded samples that are more frequently encountered. Through the capability of replicating small fragments of DNA, this latter technique also brought us into the realm of DNA microtraces, which has led to a large change in the interpretation of results. At such low levels of detection, what does it mean to the crime if a genotype consistent with an individual is observed on an evidence item? The presence or absence of such low levels of DNA can now be explained in multiple ways, potentially diminishing some of the value of DNA testing.

At this point in time, we are now on standing on the precipice of a third phase of DNA testing. The time is rapidly approaching when we may be able to identify sequence-based polymorphisms in addition to the length-based differences to which we are accustomed. This new paradigm will add an entirely new layer of data to our analysis — physical and ancestral traits. It also potentially provides us with the ability to better distinguish alternative propositions about different contributors in complex mixtures. At this early stage, it is difficult to predict exactly what the conclusions in future laboratory reports will look like; however, it is certain that they will be different than that to which we are presently accustomed.

Scientific advances are also driving how we detect and interpret the sources of DNA. Many labs throughout the world appear to be phasing out traditional serological methods and jumping directly to DNA analysis. Much of this is a result of the pressures imparted by large backlogs of untested sexual assault kits. Along these lines, it is interesting to note that investigative methods are evolving in accordance with the changes in analytical methods as a result of scrutiny placed on these kits. Some additional changes in the detection area are being thrust forward by new research on novel methods for the identification of cell types (e.g., Raman spectroscopy, messenger RNA (mRNA), and DNA methylation). These new methods hold great promise and may eventually be routinely used to provide insight on how and when stains were deposited. Of course, this will present additional challenges to the interpretation and reporting of results, but as previously mentioned, this is the nature of science.

In conjunction with scientific advances, quality must also be maintained. To this end, the Federal Bureau of Investigation (FBI) Quality Assurance Standards are currently being updated to allow for newer technologies (next generation sequencing), more sophisticated interpretation approaches (probabilistic genotyping), and specialized applications (Rapid DNA).

As we look to the future of criminalistics, our toolkit is expanding in many different directions. The Biology/DNA side of the Criminalistics Scientific Program at the AAFS 2018 Annual Scientific Meeting in Seattle, WA, will address all of these exciting potential additions to our arsenal. Presentations from both practitioners and researchers will cover mathematics, mixtures, and modeling; kinship and body identifications; new serological methods; next generation sequencing; DNA interpretation and instrumentation; DNA recovery methods; non-human DNA; and management and philosophical topics. In addition to the numerous presentations, several relevant workshops will also be offered, including a Quality Assurance Standards (QAS) Revision overview, a primer on Lean Six Sigma practices in the laboratory, and the ever-popular National Institute of Standards and Technology (NIST) Mixture Workshop. This will be your opportunity to learn at the cutting edge, expand your individual scope of knowledge, and gather new information to bring back to your lab. Some of these topics have broader appeal than just criminalistics, so bring your friends from other sections, too.

Hopefully, this will entice you to come to Seattle in February, in addition to the other great things that Seattle has to offer — coffee houses, fresh seafood, Pike Place Market, Puget Sound, the Museum of Pop Culture, and milder weather than most of us experience in the winter.

Remember, Forensic Science is a Science. And Science means change. And Science Matters.