Identifying Southwest Hispanics using nonmetric traits and the cultural profile

Due to the increasing number of Southwest Hispanics in the United States, as well as the overwhelming number of foreign nationals that die every year trying to enter the United States along the southern United States border with Mexico, new methods for classifying individuals have been established at the Pima County Office of the Medical Examiner in Tucson, Arizona (PCOME). For each of the past 5 years, the PCOME has investigated a record number of deaths associated with these border crossings. The overwhelming majority of the identified decedents are Mexican Nationals. However, approximately 25% of these undocumented border crossers have yet to be identified, making it clear that improved methods for human identification are greatly needed. The first goal of this paper is to delineate the suite of skeletal nonmetric traits utilized in assessing Southwest Hispanic ancestry at the PCOME. This suite of nonmetric traits has proven to be an effective component in establishing the "biological profile" of unknown individuals in these cases. The second goal of this paper is to introduce methods used at the PCOME to establish the "cultural profile" of individuals in these cases. The "cultural profile" is a set of identification criteria that include: the geographic context of recovery, personal effects, dental health, and cultural accoutrements. Establishing the "cultural profile" in these cases is essential in identifying individuals as foreign nationals who have died trying to cross the border.     

Identifying the dead: methods utilized by the Pima County (Arizona) office of the medical examiner for undocumented border crossers: 2001-2006

The Pima County (Arizona) Office of the Medical Examiner has seen a dramatic rise over the past 6 years in the number of deaths related to the illegal crossing of our international border with Mexico. This rise in deaths is undoubtedly related to an increase in the number of foreign nationals who cross into the various Arizona jurisdictions that utilize the Pima County Medical Examiner to investigate their unnatural deaths. Because of the utterly dangerous nature of trekking across the Sonoran Desert, especially in the summer months, many of these unfortunate migrants succumb to the effects of heat-related illness and perish along the journey. The combined effects of a dry, hot environment and the remoteness of some of the trekking corridors can quickly render a deceased person unidentifiable by visual means. Thus, our office is faced with not only an increase in the number of deaths requiring medico-legal investigation but also an increase in the number of decedents needing additional specialized examinations in an effort to effect identification. This paper attempts to outline the problems and the methods utilized by our office over the past 6 years in the identification process of undocumented border crossers. It is hoped that this paper, as well as the others presented at this symposium, will allow for the sharing of information amongst all medical investigators who assist in the identification of these migrants. The identification of these individuals takes on added importance when one considers the possible nationalities, and perhaps motivation for entering into the US, of those that remain unidentified.     

A survey of background levels of explosives and related compounds in the environment

In this paper, swabbings from various public areas in 28 different cities throughout the United States were collected. A wide variety of objects were tested, ranging from park benches and telephones to sign posts and mailboxes. Inorganic anions and cations common in low explosives were detected simultaneously using capillary zone electrophoresis. Organic high explosives including nitroaromatics, nitramines, and nitrate esters were detected using gas chromatography with a pulsed-discharge electron capture detector. Confirmation of selected results was performed by ion chromatography and negative ion chemical ionization GC/MS. In general the results provide two major conclusions: (i) with the exception of nitrate, most low explosive oxidizers are rare in the environment; (ii) no organic explosives or significant interferences to these explosives were detected.     

Evaluation and quantification of nuclear DNA from human telogen hairs

Nuclear DNA was extracted from human telogen hairs from 60 individuals. Six to nine hairs from each individual were individually extracted. The amount of DNA recovered from each individual varied greatly, and most samples yielded a quantity of 550 pg or less per hair. A selective extraction buffer was used to remove epithelial cell DNA and the amount of exogenous DNA was determined. DNA was also quantified by real time PCR using three different sized amplicons targeting an Alu sequence. The results were used to determine the state of degradation of the extracted DNA. Different quantities of sample (<100 pg, 100-500 pg, >500 pg) were amplified with the Miniplex kits to determine the minimum DNA template required for successful amplification. DNA recovered from hair showed degradation; however, partial profiles were obtained for those samples containing at least 60 pg using MiniSTRs.     

Development of a Nomenclature System for a Canine STR Multiplex Reagent Kit*†

Abstract: Despite the popularity of dogs in US households, canine DNA evidence remains largely untapped in forensic investigations partially because of the absence of well‐defined forensic short tandem repeats (STRs), lack of standardized and validated PCR protocols, STR reagent kits, and poorly developed nomenclature. A nomenclature system was established based on internationally recognized recommendations for human forensic STRs for a recently developed canine STR reagent kit. Representative alleles were sequenced from each of the 18 STRs and the sex‐typing marker included in the kit. This study also reflects on the impact of point mutations, insertions, and deletions within and outside the STR core repeat structures. An understanding of the STRs’ sequence and repeat structures will enable development of a robust and reliable allele nomenclature and improve the accuracy and precision of allele fragment sizing in canine forensic profiling. The expected allele sizes have been calculated, and their repeat stuctures defined based on sequence information.     

Micellar electrokinetic chromatographic screening method for common sexual assault drugs administered in beverages

Recently, much attention has been given to benzodiazepines and gamma-hydroxybutyric acid (GHB) related compounds owing to their alleged widespread use as date-rape drugs. Toxicologists would greatly benefit from a screening method that allows for the simultaneous detection of both groups of substances. A new capillary electrophoresis (CE) method has been developed in the micellar mode to accomplish this separation in under 16 min using a sodium dodecyl sulfate (SDS)/sodium tetraborate/boric acid buffer with an acetonitrile organic modifier. Optimization of SDS and organic modifier concentration, along with pH, were performed on a set of standards containing eight benzodiazepines, GHB, gamma-butyrolactone, and the internal standard, sulfanilic acid. The method was shown to have a detection limit of less than 2 microg/ml for five out of eight benzodiazepines with a linear range of 2.5-100 microg/ml. The detection limit for GHB was 32 mg/ml with a linear range to 2500 microg/ml. This method was applied to the rapid analysis of spiked beverages. GHB spiked beverages were monitored after using a series of simple dilutions to determine the effects of time on the drug analysis. Possible interfering peaks from drugs of abuse and artifacts from a variety of different drink combinations were also studied in detail. A one-step liquid-liquid extraction was the only necessary sample pretreatment.