Developing an Empirically Based Ranking Order for Bone Sampling: Examining the Differential DNA Yield Rates Between Human Skeletal Elements Over Increasing Post Mortem Intervals

The research determined which skeletal elements within a single individual were most likely to provide both the quantity and quality of DNA needed to produce DNA profiles from increasing post-mortem intervals. The study determined that cancellous bones (phalanx, patella, and tarsal's), typically dismissed as a potential DNA source in favor of dense cortical bones, should be reconsidered when sampling. Results for the tibia and femur did not reach the specifications to qualify for PMI testing; however, they are elements practitioners typically prefer to sample. By determining which skeletal element is most likely to yield a single tandem repeat (STR) profile, thus allowing identification expensive and time-consuming retesting can be avoided. Currently, selecting skeletal elements for DNA testing is based on the collective wisdom of practitioners who suggest using weight-bearing long bones over all other skeletal elements, recent evidence questions the accuracy of this collective wisdom. Regarding DNA yield at various PMI's, less complete DNA profiles were produced as the PMI increased. A two-phase study was conducted. Phase I involved analyzing the DNA yield rates of various skeletal elements from three recently skeletonized individuals, with the intent of producing an overall rank order from most successful to least successful. Phase II was designed to determine whether the same elements from Phase I were equally successful at longer post-mortem intervals (0-3, 4-10, 11-20, and 20+ years) and to record how DNA degradation occurs over time. 121 references, 8 tables, 11 figures, and information on the dissemination of research findings