The effects of skeletal preparation techniques on DNA from human and non-human bone

The forensic pathologist increasingly relies on the forensic anthropologist to be the consulting expert in human identification. Likewise, if identification is not possible from visual inspection of skeletal remains, the forensic biologist may be called upon to conduct DNA analysis. The possibility of downstream DNA testing needs to be considered when skeletal preparation techniques are employed to deflesh human remains, as they have the potential to strongly impact genetic analyses and subsequent identification. In this study, three cleaning techniques, boiling bone in water, in bleach, and in powdered detergent/sodium carbonate, were tested for their effect on nuclear and mtDNA recovery from a variety of human and non-human bones. A statistically significant reduction in DNA yields occurred in non-human bones cleaned with bleach, and DNA degradation was apparent electrophoretically. The human bones also showed much lower yields from bleach cleaning, while the detergent/carbonate method allowed the largest segments of DNA to be amplified, indicating it may have a less degradative effect on bone DNA than either of the other cleaning processes.     

The fingernails of Mary Sullivan: developing reliable methods for selectively isolating endogenous and exogenous DNA from evidence

The fingernails of Mary Sullivan, the last victim of the Boston Strangler, were examined to determine if any genetic information about the murderer could be obtained. The nails were extremely friable necessitating the development of new techniques for isolating and purifying DNA. DNA yields from nails were optimized by using a NaOH-based preparation technique, which was simple, efficient, and minimized handling. Methods for selectively and thoroughly removing exogenous material on nails were also developed through use of a species-specific PCR assay, wherein mitochondrial DNA from the nail could easily be differentiated from DNA of contaminating cells.     

Problem Drinking, Jealousy, and Anger Control: Variables Predicting Physical Aggression Against a Partner

Alcohol use and intimate partner violence (IPV) are significantly related, but only a subset of individuals who drink are aggressive and relatively little is known about what moderates this relationship in community samples. Two risk factors, anger control and jealousy, were hypothesized to moderate the relationship between IPV and problem drinking in a sample of 453 community couples. A significant three-way interaction indicated that men with jealousy problems, but not anger control problems, were most likely to show the strongest association between problem drinking and IPV. In accord with the multiple threshold model of IPV, specific combinations of risk factors appeared to represent different thresholds in which problem drinking influenced the likelihood of IPV.     

Collecting and Analyzing DNA Evidence from Fingernails: A Comparative Study,,

Forensic practitioners and crime laboratories regularly collect and analyze fingernail evidence; however, the best techniques for processing such evidence have not been established. In this study, numerous aspects of fingernail evidence processing—collection of exogenous cells, transportation, purification of DNA, and STR analysis—were analyzed using fingernails harboring applied blood or epithelial cells from scratchings. Autosomal STR mixtures resulted when fingernails were soaked or swabbed, while scrapings rarely generated mixtures but exhibited allelic dropout. Y‐STRs yielded single source profiles, with scrapings again showing dropout. A silica‐based kit extraction recovered significantly more exogenous DNA than did organic extraction, neither of which was affected by nail polish. Swabbing nails in succession resulted in some cross‐contamination from exogenous material, while transporting nails together did not, although there was loss of exogenous cells. Optimized nail processing produced complete Y‐STR profiles of male volunteers from female fingernails following scratchings.     

Investigative studies into the recovery of DNA from improvised explosive device containers

Apprehending those who utilize improvised explosive devices (IEDs) is a national priority owing to their use both domestically and abroad. IEDs are often concealed in bags, boxes, or backpacks to prevent their detection. Given this, the goal of the research presented was to identify IED handlers through postblast DNA recovery from IED containers. Study participants were asked to use backpacks for 11 days, after which they served as containers for pipe bombs. Eleven postdeflagration backpack regions likely to be handled were swabbed and analyzed via mini-short tandem repeats (miniSTRs) and alleles were called blind. An experimental consensus method was examined in which profiles from all regions were considered, to help identify spurious drop-in/out. Results were correct for all loci, except one that remained ambiguous. The results show that recovering DNA from IED containers is a viable approach for aiding in the identification of those who may have been involved in an IED event.     

Generalized additive models and Lucilia sericata growth: assessing confidence intervals and error rates in forensic entomology

Forensic entomologists use blow fly development to estimate a postmortem interval. Although accurate, fly age estimates can be imprecise for older developmental stages and no standard means of assigning confidence intervals exists. Presented here is a method for modeling growth of the forensically important blow fly Lucilia sericata, using generalized additive models (GAMs). Eighteen GAMs were created to predict the extent of juvenile fly development, encompassing developmental stage, length, weight, strain, and temperature data, collected from 2559 individuals. All measures were informative, explaining up to 92.6% of the deviance in the data, though strain and temperature exerted negligible influences. Predictions made with an independent data set allowed for a subsequent examination of error. Estimates using length and developmental stage were within 5% of true development percent during the feeding portion of the larval life cycle, while predictions for postfeeding third instars were less precise, but within expected error.     

Assessing the Utility of Soil DNA Extraction Kits for Increasing DNA Yields and Eliminating PCR Inhibitors from Buried Skeletal Remains

DNA identification of human remains is often necessary when decedents are skeletonized; however, poor DNA recovery and polymerase chain reaction (PCR) inhibition are frequently encountered, a situation exacerbated by burial. In this research, the utility of integrating soil DNA isolation kits into buried skeletal DNA analysis was evaluated and compared to a standard human DNA extraction kit and organic extraction. The soil kits successfully extracted skeletal DNA at quantities similar to standard methods, although the two kits tested, which differ mechanistically, were not equivalent. Further, the PCR inhibitors calcium and humic acid were effectively removed using the soil kits, whereas collagen was less so. Finally, concordant control region sequences were obtained from human skeletal remains using all four methods. Based on these comparisons, soil DNA isolation kits, which quickened the extraction process, proved to be a viable extraction technique for skeletal remains that resulted in positive identification of a decedent.     

INNOVATIVE APPROACHES IN CHILD CUSTODY EVALUATIONS

This article discusses the joint office interview as an innovative technique for evaluation of families, the feedback or "summary" sessions by evaluators, and the role of the mediator in the feedback process. A retrospective analysis of the procedures revealed that considerable material could be studied and presented. Summaries of these data are offered as a guide to those interested in the resolution of child custody disputes.