Assessing a novel room temperature DNA storage medium for forensic biological samples

The ability to properly collect, analyze and preserve biological stains is important to preserving the integrity of forensic evidence. Stabilization of intact biological evidence in cells and the DNA extracts from them is particularly important since testing is generally not performed immediately following collection. Furthermore, retesting of stored DNA samples may be needed in casework for replicate testing, confirmation of results, and to accommodate future testing with new technologies.A novel room temperature DNA storage medium, SampleMatrix™ (SM; Biomatrica, Inc., San Diego, CA), was evaluated for stabilizing and protecting samples. Human genomic DNA samples at varying amounts (0.0625-200 ng) were stored dry in SM for 1 day to 1 year under varying conditions that included a typical ambient laboratory environment and also through successive freeze-thaw cycles (3 cycles). In addition, spiking of 1-4× SM into samples prior to analysis was performed to determine any inhibitory effects of SM. Quantification of recovered DNA following storage was determined by quantitative PCR or by agarose gel electrophoresis, and evaluation of quantitative peak height results from multiplex short tandem repeat (STR) analyses were performed to assess the efficacy of SM for preserving DNA.Results indicate no substantial differences between the quality of samples stored frozen in liquid and those samples maintained dry at ambient temperatures protected in SM. For long-term storage and the storage of low concentration samples, SM provided a significant advantage over freezer storage through higher DNA recovery. No detectable inhibition of amplification was observed at the recommended SM concentration and complete profiles were obtained from genomic DNA samples even in the presence of higher than recommended concentrations of the SM storage medium. The ability to stabilize and protect DNA from degradation at ambient temperatures for extended time periods could have tremendous impact in simplifying and improving sample storage conditions and requirements. The current work focuses on forensics analysis; however this technology is applicable to all endeavors requiring storage of DNA.     

Urgent issues and prospects at the intersection of culture,memory, and witness interviews: Exploring the challenges for research and practice

The pursuit of justice increasingly relies on productive interactions between witnesses and investigators from diverse cultural backgrounds during investigative interviews. To date, the role of cultural context has largely been ignored by researchers in the field of investigative interviewing, despite repeated requests from practitioners and policymakers for evidence-based guidance for the conduct of interviews with people from different cultures. Through examining cultural differences in human memory and communication and considering specific contextual challenges for investigative interviewing through the lens of culture, this review and associated commentaries highlight the scope for considering culture and human diversity in research on, and the practice of, investigative interviewing with victims, witnesses, and other sources. Across 11 commentaries, contributors highlight the importance of considering the role of culture in different investigative interviewing practices (e.g., rapport building, questioning techniques) and contexts (e.g., gender-based violence, asylum seeking, child abuse), address common areas of cultural mismatch between interviewer–interviewee expectations, and identify critical future routes for research. We call for an increased focus in the investigative interviewing literature on the nature and needs of our global community and encourage constructive and collaborative discussion between researchers and practitioners from around the world to better identify specific challenges and work together towards evidence-based solutions.