Lodox®: the invaluable radiographic solution in the forensic setting

International Journal of Legal Medicine - The benefits of a comparatively inexpensive radiographic system such as the Lodox® scanner in forensic facilities where CT-imaging and radiologist...     

Fitting the Balding–Nichols model to forensic databases

Large forensic databases provide an opportunity to compare observed empirical rates of genotype matching with those expected under forensic genetic models. A number of researchers have taken advantage of this opportunity to validate some forensic genetic approaches, particularly to ensure that estimated rates of genotype matching between unrelated individuals are indeed slight overestimates of those observed. However, these studies have also revealed systematic error trends in genotype probability estimates. In this analysis, we investigate these error trends and show how they result from inappropriate implementation of the Balding–Nichols model in the context of database-wide matching. Specifically, we show that in addition to accounting for increased allelic matching between individuals with recent shared ancestry, studies must account for relatively decreased allelic matching between individuals with more ancient shared ancestry.     

Do forensic physicians have a future in the UK?

This article represents a personal view of the future of forensic physicians (police surgeons) in the UK.     

Entomotoxicology for the forensic toxicologist: much ado about nothing?

We present a series of 29 necropsies in which organic compounds (including benzodiazepines, barbiturates, antidepressants, phenothiazine, opiates, cannabinoids, meprobamate, digoxin and nefopam) were detected in arthropod larvae sampled on human corpses. No correlation was observed between drug concentrations in the larvae versus human samples. When tested, inter-larvae and inter-site variations of drug concentrations (i.e., within larvae when analyzed separately, and within anatomic sites when larvae were grouped according to their site of sampling) were enormous and not reproducible from one case to another, confirming that arthropod larvae are unreliable for quantitative toxicological analysis. Since drugs identified in maggots are always detectable in the cadaver too, we conclude that larvae analysis is of almost no interest for practical forensic casework.     

Intra vitam trauma pattern: changing the paradigm of forensic anthropology?

International Journal of Legal Medicine - This study aims to improve a previous study that reported new traits to characterize a perimortem fracture pattern in human long bones. This second study...     

Forensic intelligence: deregulation or return to the roots of forensic science?

This paper presents an overview of forensic intelligence through historical, operational and academic considerations. While forensic intelligence is thriving through new traceability of human activities, theoretical developments in policing and innovative technologies, it should mainly be seen as an opportunity for forensic science to contribute to making policing more ‘scientific’ in the broad sense. This paper supports the development of a modern framework to holistically use the information conveyed by forensic case data to inform policing processes, support decision-making and ensure transparency. It is argued that the scientific information, the trace, has to be privileged, rather than rejected from current debates, despite the potential fears prompted by the misinterpretation of the term ‘intelligence’. Ultimately, forensic intelligence enables the emergence of a modern conception of forensic science.     

Experience with the PCR-based HLA-DQα DNA typing system in routine forensic casework

Summary The results of HLA-DQ typing from 42 routine forensic cases using the polymerase chain reaction (PCR) were analyzed regarding the reliability, discrimination efficiency and informative value of this system in a given case. The cases included stain typing from a variety of different substrates, i.e. blood and semen stains, mixed body fluids, single hairs, cigarette butts, material from fingernail scratches, as well as identification and paternity cases on postmortem and fixed tissue. A total of 125 individual stain and tissue samples were included. PCR amplification was achieved in 70% of these samples. In cases with mixed body fluids, e.g. sperm and vaginal cells from rape cases, DQ typing was always carried out successfully. However, only approx. 42% of all samples that could be typed were relevant regarding the inclusion or exclusion of a suspect. This was mostly due to the limited number of alleles that can be typed at the HLA-DQ locus or to the fact that the stain or hair samples did not originate from the perpetrator, but from the victim or from other persons not related to the crime.     

CT of the medial clavicular epiphysis for forensic age estimation: hands up?

International Journal of Legal Medicine - The aim of this study was to assess the impact of arm position in computed tomography (CT) of the clavicle performed for forensic age estimation on...     

Radiographic evaluation of Gustafson’s criteria for the purpose of forensic age diagnostics

The main criteria used in dental age estimation in living young individuals are mineralisation and eruption of the third molars. In order to further diversify the spectrum of characteristics after completion of third molar development, tests were undertaken to determine whether the characteristics studied by Gustafson can be ascertained with the required forensic certainty with the aid of the orthopantomogram and whether the evaluation of these could render forensic odontological age diagnoses possible beyond the 18th year of life. For this purpose, 1,299 conventionally produced orthopantomograms of 650 female and 649 male Germans aged from 15 to 40?years were studied. The characteristics of secondary dentin formation, cementum apposition, periodontal recession and attrition were evaluated in all the mandibular premolars. The correlation of the individual characteristics with chronological age was studied with the aid of a multiple regression analysis in which chronological age formed the dependent variable. Depending on the tooth studied, the R values amounted to 0.65 to 0.73; the standard error of estimate was 5.3 to 5.7?years. Basically, the regression equations calculated can be recommended for age estimation in living individuals, although it should be borne in mind that the applicability of the new method presented is limited by the quality of the X-ray images.     

Case report: on the use of the HID-Ion AmpliSeq™ Ancestry Panel in a real forensic case

International Journal of Legal Medicine - In the absence of any other conclusive forensic evidence, DNA profiling is the method of choice for body identification. This study focuses on the case of...     

Application of the new insertion–deletion polymorphism kit for forensic identification and parentage testing on the Czech population

Insertion-deletion polymorphisms (INDELs) are diallelic markers derived from a single mutation event. Their low mutation frequency makes them suitable for forensic and parentage testing. The examination of INDELs thus combines advantages of both short tandem repeats (STR) and single nucleotide polymorphisms (SNP). This type of polymorphisms may be examined using as small amplicon size as SNP (about 100 bp) but could be analyzed by techniques used for routine STR analysis. For our population study, we genotyped 55 unrelated Czech individuals. We also genotyped 11 trios to analyze DIPplex Kit (QIAGEN, Germany) suitability for parentage testing. DIPplex Kit contains 30 diallelic autosomal markers. INDELs in DIPplex Kit were tested with linkage disequilibrium test, which showed that they could be treated as independent markers. All 30 loci fulfill Hardy–Weinberg equilibrium. There were several significant differences between Czech and African populations, but no significant ones within European population. Probability of a match in the Czech population was 1 in 6.8?×?10¹²; combined power of discrimination was 99.9999999999%. Average paternity index was 1.13–1.77 for each locus; combined paternity index reached about 27,000 for a set of 30 loci. We can conclude that DIPplex kit is useful as an additional panel of markers in paternity cases when mutations in STR polymorphisms are present. For application on degraded or inhibited samples, further optimization of buffer and primer concentrations is needed.     

Reference data for the Thiemann–Nitz method of assessing skeletal age for the purpose of forensic age estimation

The aim of this study was to determine the statistical parameters of deviation in the Thiemann–Nitz method for use in forensic age diagnostics. To this effect, 402 hand radiograms, originally taken in two large German cities between 1983 and 2002 for the purpose of diagnosing trauma, were analyzed. At the time of examination, the patients were aged between 10 and 18 years. The study presents the mean, standard deviation, and median, with lower and upper quartiles, for the skeletal ages of 11.0 through 18.0 years. The simple standard deviations range between 0.2 and 1.2 years. To increase the accuracy of age estimates and improve the identification of age-relevant developmental disorders in forensic age estimation practice, the methods for determining skeletal age should always be combined with a physical and dental examination. In addition, the expert opinion should pay attention to the issue of different modernization levels in relevant populations.     

Second-generation sequencing of forensic STRs using the Ion Torrent™ HID STR 10-plex and the Ion PGM™

Second-generation sequencing (SGS) using Roche/454 and Illumina platforms has proved capable of sequencing the majority of the key forensic genetic STR systems. Given that Roche has announced that the 454 platforms will no longer be supported from 2015, focus should now be shifted to competing SGS platforms, such as the MiSeq (Illumina) and the Ion Personal Genome Machine (Ion PGM™; Thermo Fisher). There are currently several challenges faced with amplicon-based SGS STR typing in forensic genetics, including current lengths of amplicons for CE-typing and lack of uniform data analysis between laboratories.Thermo Fisher has designed a human identification (HID) short tandem repeat (STR) 10-plex panel including amelogenin, CSF1PO, D16S539, D3S1358, D5S818, D7S820, D8S1179, TH01, TPOX and vWA, where the primers have been designed specifically for the purpose of SGS and the data analysis is supported by Ion Torrent™ software. Hence, the combination of the STR 10-plex and the Ion PGM™ represents the first fully integrated SGS STR typing solution from PCR to data analysis.In this study, four experiments were performed to evaluate the alpha-version of the STR 10-plex: (1) typing of control samples; (2) analysis of sensitivity; (3) typing of mixtures; and (4) typing of biological crime case samples. Full profiles and concordant results between replicate SGS runs and CE-typing were observed for all control samples. Full profiles were seen with DNA input down to 50 pg, with the exception of a single locus drop-out in one of the 100 pg dilutions. Mixtures were easily deconvoluted down to 20:1, although alleles from the minor contributor had to be identified manually as some signals were not called by the Ion Torrent™ software. Interestingly, full profiles were obtained for all biological samples from real crime and identification cases, in which only partial profiles were obtained with PCR-CE assays. In conclusion, the Ion Torrent™ HID STR 10-plex panel offers an all-in-one solution from amplification of STRs and amelogenin, and sequencing to data analysis.     

Evaluation of forensic genetic parameters of 12 STR loci in the Korean population using the InvestigatorⓇ HDplex kit

We genotyped and calculated the forensic parameters of 10 non-CODIS loci and 2 CODIS loci of 990 Korean individuals using the Investigator^Ⓡ HDplex kit. No significant deviations from Hardy–Weinberg equilibrium (after Bonferroni correction for multiple testing) or genetic linkage disequilibrium were observed. The calculated matching probability and power of discrimination ranged from 0.0080 to 0.2014, and 0.7986 to 0.9920, respectively. We conclude that the markers of the kit are highly informative corroborative tools for forensic DNA analysis.

     

Is the amelogenin gene reliable for gender identification in forensic casework and prenatal diagnosis?

In humans, the amelogenin gene is present on both the X and the Y chromosomes. However, there are size differences in this gene between these chromosomes, which have been utilised for sexing in forensic casework and prenatal diagnosis. Our study using the AmpFl STR Profiler Plus kit, showed a deletion of Y chromosome-specific amelogenin in five Indian males (1.85%). We propose to call them “deleted-amelogenin males” (DAMs), who but for the detection of the presence of other Y-specific markers (e.g. SRY, STR and 50f2) would have been identified as females. Considering the consequences of the result obtained only using the amelogenin marker, we suggest the use of additional Y chromosome markers for unambiguous gender identification. Received: 17 May 2001 / Accepted: 24 July 2001     

Inter-laboratory evaluation of SNP-based forensic identification by massively parallel sequencing using the Ion PGM™

Next generation sequencing (NGS) offers the opportunity to analyse forensic DNA samples and obtain massively parallel coverage of targeted short sequences with the variants they carry. We evaluated the levels of sequence coverage, genotyping precision, sensitivity and mixed DNA patterns of a prototype version of the first commercial forensic NGS kit: the HID-Ion AmpliSeq™ Identity Panel with 169-markers designed for the Ion PGM™ system. Evaluations were made between three laboratories following closely matched Ion PGM™ protocols and a simple validation framework of shared DNA controls. The sequence coverage obtained was extensive for the bulk of SNPs targeted by the HID-Ion AmpliSeq™ Identity Panel. Sensitivity studies showed 90–95% of SNP genotypes could be obtained from 25 to 100 pg of input DNA. Genotyping concordance tests included Coriell cell-line control DNA analyses checked against whole-genome sequencing data from 1000 Genomes and Complete Genomics, indicating a very high concordance rate of 99.8%. Discordant genotypes detected in rs1979255, rs1004357, rs938283, rs2032597 and rs2399332 indicate these loci should be excluded from the panel. Therefore, the HID-Ion AmpliSeq™ Identity Panel and Ion PGM™ system provide a sensitive and accurate forensic SNP genotyping assay. However, low-level DNA produced much more varied sequence coverage and in forensic use the Ion PGM™ system will require careful calibration of the total samples loaded per chip to preserve the genotyping reliability seen in routine forensic DNA. Furthermore, assessments of mixed DNA indicate the user’s control of sequence analysis parameter settings is necessary to ensure mixtures are detected robustly. Given the sensitivity of Ion PGM™, this aspect of forensic genotyping requires further optimisation before massively parallel sequencing is applied to routine casework.     

Unraveling the mystery of confiscated “jackal horns” in India using wildlife forensic tools

International Journal of Legal Medicine - Internationally, illegal wildlife trade involves highly prized and charismatic species and their derivatives. At the same time, common or less known...