DNA methylation patterns change during human lifetime; thus, they can be used to estimate an individual's age. It is known, however, that correlation between DNA methylation and aging might not be linear and that the sex might influence the methylation status. In this study, we conducted a comparative evaluation of linear and several non-linear regressions, as well as sex-specific versus unisex models. Buccal swab samples from 230 donors aged 1 to 88 years were analyzed using a minisequencing multiplex array. Samples were divided into a training set (n = 161) and a validation set (n = 69). The training set was used for a sequential replacement regression and a simultaneous 10-fold cross-validation. The resulting model was improved by including a cut-off of 20 years, dividing the younger individuals with non-linear from the older individuals with linear dependence between age and methylation status. Sex-specific models were developed and improved prediction accuracy in females but not in males, which might be explained by a small sample set. We finally established a non-linear, unisex model combining the markers EDARADD, KLF14, ELOVL2, FHL2, C1orf132, and TRIM59. While age- and sex-adjustments did not generally improve the performance of our model, we discuss how other models and large cohorts might benefit from such adjustments. Our model showed a cross-validated MAD and RMSE of 4.680 and 6.436 years in the training set and of 4.695 and 6.602 years in the validation set, respectively. We briefly explain how to apply the model for age prediction.

The reproducibility of stem cell research relies on the constant availability of quality-controlled cells. As the quality of human induced pluripotent stem cells (hiPSCs) can deteriorate in the course of a few passages, cell banking is key to achieve consistent results and low batch-to-batch variation. Here, we provide a cost-efficient route to generate master and working cell banks for basic research projects. In addition, we describe minimal protocols for quality assurance including tests for sterility, viability, pluripotency, and genetic integrity. © 2020 The Authors. Basic Protocol 1: Expansion of hiPSCs Basic Protocol 2: Cell banking of hiPSCs Support Protocol 1: Pluripotency assessment by flow cytometry Support Protocol 2: Thawing control: Viability and sterility Support Protocol 3: Potency, viral clearance, and pluripotency: Spontaneous differentiation and qRT-PCR Support Protocol 4: Identity: Short tandem repeat analysis.

This study provides 398 novel complete mitochondrial control region sequences that augment the still underrepresented data from Africa by three datasets: a mixed West African sample set deriving from 12 countries (n = 145) and datasets from Côte d’Ivoire (Ivory Coast) (n = 100) as well as Rwanda (n = 153). The analysis of mtDNA variation and genetic comparisons with published data revealed low random match probabilities in all three datasets and typical West African and East African diversity, respectively. Genetic parameters indicate that the presented mixed West African dataset may serve as first forensic mtDNA control region database for West Africa in general. In addition, a strategy for responsible forensic application of precious mtDNA population samples potentially containing close maternal relatives is outlined. The datasets will be uploaded to the forensic mtDNA database EMPOP (https://empop.online) upon publication.

In cases of crimes involving blood, the perpetrators often attempt to remove the traces they have left behind. Setting fire to the crime scene, aside from cleaning measures, seems to achieve this goal and presents a major challenge for crime scene investigators. There is only very little published information available on the effect of fire and extreme heat on blood and the detection thereof. After exposure to high temperatures of or exceeding 1.000 °C, blood is deemed to be undetectable. This study exposed 11 different potentially crime-relevant objects using a standardized and controlled procedure to temperatures of 300 °C, 700 °C, and 1.000 °C documenting the influence of heat on bloodstains and the detection of blood. The results of the forensic collection of blood traces with and without liquid latex confirmed the advantage of using the latex method. Almost all objects showed a clear luminescence-caused visualization of traces of blood after removing the soot with a latex lift. There were also fewer false positive results than in tests not using latex.

Each forensic case is characterized by its own uniqueness. Deficient forensic cases require additional sources of human identifiers to assure the identity. We report on two different cases illustrating the role of teeth in answering challenging forensic questions. The first case involves identification of an adipocere male found in a car submersed in water for approximately 2 years. The second scenario, which involves paternity DNA testing of an exhumed body, was performed approximately 2.8 years post-mortem. The difficulty in anticipating the degradation of the DNA is one of the main obstacles. DNA profiling of dental tissues, DNA quantification by using real-time PCR (PowerQuant™ System/Promega) and a histological dental examination have been performed to address the encountered impediments of adverse post-mortem changes. Our results demonstrate that despite the adverse environmental conditions, a successful STR profile of DNA isolated from the root of teeth can be generated with respect to tooth type and apportion. We conclude that cementocytes are a fruitful source of DNA. Cementum resists DNA degradation in comparison to other tissues with respect to the intra- and inter-individual variation of histological and anatomical structures.

The analysis of blood traces is often of significant reconstructive and evidence-gathering importance. Perpetrators deliberately set fires to destroy evidence. There is little literature regarding the effect of fire and extreme heat on blood and the detection of blood. Blood and DNA are believed to be no longer traceable after exposure to a temperature of 1000 °C. This study exposed different objects of a standardized procedure to temperatures of 300, 700, and 1000 °C. It documented the influence of heat on blood traces through the use of luminol. DNA analysis confirmed that fewer DNA profiles can be created with increasing temperature. However, even after exposure up to a max. of 1000 °C, it was still possible to produce a complete DNA pattern from approx. 60% of the samples. Consequently, crime scenes that have been destroyed by fire should be evaluated with the same attention to detail as the unburned areas.

Luminol has been used for a long time for detecting latent blood traces during police investigations because it is easy to use and does not pose any health risks, while providing trace evidence for DNA analysis. It is often the method of choice for examining clothing. Clothes worn during the offense are often destroyed or washed afterwards by the offenders. The purpose of this study is to show the possibilities of blood and DNA detection on washed clothes by documenting the macroscopic results and their chemiluminescence after washing. The tests comprised different fabrics and laundry detergents including different washing and drying methods. Chemiluminescence was detected on almost all blood-marked samples (95.9%), even after all traces visible to the naked eye have been removed by washing. Evidence of a complete DNA profile or individual alleles could be confirmed in almost all of the test cases (93.3%).

This paper discusses the discovery of a skeletonized water corpse with hollow bones filled with adipocere found in the tidelands of the river Elbe close to Otterndorf (Wesermarsch, Cuxhaven). Through macroscopic and microscopic methods, the existing adipocere was described. The post-mortem interval was assessed by a comparison of the radiocarbon data and the indications about the preservation of adipocere from the literature.The investigation has shown that the knowledge of post-mortem changes in adipocere within bone structures is still incomplete, especially for the assessment of water corpses with long post-mortem intervals.

The article reports on the exhumation and identification of unknown soldiers from the Second World War. With the help of medicolegal investigation and reconstruction methods an American pilot presumably murdered by a shot to the head (lynch law) and an interned Italian soldier could be identified after about 70 years and brought back home.

The aim of this study was to clarify whether positive results for prostate-specific antigen (PSA) and acid phosphatase (AP) occur in postmortem swabs from the genito-anal region in males (n = 80; 4 regions) and females (n = 20; 3 regions) and to calculate the positive predictive value (PPV) concerning the presence of spermatozoa. In male subjects, the highest incidence of positive test results was found in urethral swabs (PSA 76%, AP 71%) and the lowest frequencies appeared in perianal and rectal swabs (15-20%). Microscopic evaluation for spermatozoa was positive between 39% in urethral swabs and 1% in rectal swabs. PPV regarding positive identification of spermatozoa was 33.3% for PSA and 31.5% for AP. The combination of both tests yielded a PPV of 38.2%. In female cases, no spermatozoa were identified, and one case was PSA- and AP-positive in perianal swabs. Our findings indicate that PSA and AP tests are of limited value for the postmortem detection of spermatozoa in male subjects.

The topic of this article is sexual violence in context with war-like conflicts in the former Yugoslavia and Rwanda. The fundamental categories of sexual violence in war-like conflicts are described. The authors discuss the types of sexual violence as defined in the report of the UN Commission of Experts on the war-like conflicts in the former Yugoslavia. Four criminal trials were evaluated: three held before the International Criminal Tribunal for the Former Yugoslavia (ICTY) in The Hague/Netherlands and one before the International Criminal Tribunal for Rwanda (ICTR) in Arusha/Tansania. The defendants were found guilty of torture, crime against humanity and genocide. Potential procedures with respect to similar crimes in current or prospective conflicts are discussed. An alternative may be the assignment of medical personnel (for example of the German Federal Armed Forces). Finally, the post-war cooperation between the Institute of Legal Medicine at the University Medical Centre of Hamburg-Eppendorf as well as the medical and government institutions in Rwanda is presented, which has been going on since 2005.

Genetic polymorphisms in cytochrome P 450 (CYP) enzymes could lead to a phenotype with altered enzyme activity. In pharmacotherapy, genotype-based dose recommendations achieved great importance for several drugs. In our pilot study, we ask if these genetic tests should be applied to forensic problems as a matter of routine. Starting from 2004 through 2008, we screened routine cases for samples where the relation of parent compound to metabolite(s) (P/M ratio), particularly morphine to codeine ratios and diazepam to its metabolites, was noticeable or not consistent with the information provided by the defendants. We found 11 samples with conspicuous results. These were analyzed for polymorphisms of the CYP 2D6 and 2C19 genes using the Roche AmpliChip Cytochrome P450 Genotyping test. If not previously conducted, a general unknown analysis by gas chromatography/mass spectrometry (GC/MS) was additionally carried out. For CYP 2D6, we found two cases with the genotype poor metabolizer (PM), three cases with heterozygote extensive metabolizer genotype classified as an intermediate metabolizer (IM) with probably reduced enzyme activities, but no ultrarapid metabolizer genotype. For CYP 2C19, two cases were characterized as IM phenotypes, with no PM found. Once we achieved no appropriate amounts of DNA, one case was excluded after GC/MS analysis. Only in one case could the polymorphism clearly explain the changes in drug metabolism. More frequently, a drug–drug interaction was thought to have a stronger impact. Additionally, our results suggest that IM genotypes may be more relevant than previously suspected. With respect to the small number of cases in which we thought a genotyping would be helpful, we conclude that the overall relevance of toxicogenetics in forensic problems is moderate. However, in some individual cases, a genotyping may provide new insight.

A large number of short tandem repeat (STR) markers spanning the entire human X chromosome have been described and established for use in forensic genetic testing. Due to their particular mode of inheritance, X-STRs often allow easy and informative haplotyping in kinship analyses. Moreover, some X-STRs are known to be tightly linked so that, in combination, they constitute even more complex genetic markers than each STR taken individually. As a consequence, X-STRs have proven particularly powerful in solving complex cases of disputed blood relatedness. However, valid quantification of the evidence provided by X-STR genotypes in the form of likelihood ratios requires that the recombination rates between markers are exactly known. In a collaborative family study, we used X-STR genotype data from 401 two- and three-generation families to derive valid estimates of the recombination rates between 12 forensic markers widely used in forensic testing, namely DXS10148, DXS10135, DXS8378 (together constituting linkage group I), DXS7132, DXS10079, DXS10074 (linkage group II), DXS10103, HPRTB, DXS10101 (linkage group III), DXS10146, DXS10134 and DXS7423 (linkage group IV). Our study is the first to simultaneously allow for mutation and recombination in the underlying likelihood calculations, thereby obviating the bias-prone practice of excluding ambiguous transmission events from further consideration. The statistical analysis confirms that linkage groups I and II are transmitted independently from one another whereas linkage groups II, III and IV are characterised by inter-group recombination fractions that are notably smaller than 50%. Evidence was also found for recombination within all four linkage groups, with recombination fraction estimates ranging as high as 2% in the case of DXS10146 and DXS10134.

The STR markers DXS6795, DXS9907 and GATA144D04 are located on the short arm in the region Xp22.11-Xp11.23. These loci were typed from buccal swab samples from unrelated German individuals ( 161 male, 362 female). Additionally, DNA from 90 males with one ore more daughters and their 135 grandsons were typed to check for mutability of these loci. German population and sequencing data for these three loci as well as statistical parameters of forensic interest are presented. DNA typing patterns of cell lines were used as intra-and inter-laboratory standards to calibrate allelic ladders. We found 8 different alleles in DXS9907 and GATA144D04, whereas DXS6795 exhibited only 6 alleles. Allelic distribution patterns are identical for males and females. There is no evidence for deviation from the Hardy-Weinberg equilibrium in female samples. Furthermore, no mutations were detected within 90 paternal and 135 maternal meioses. The three microsatellites are moderately variable with PIC values of 0.61, 0.56 and 0.70. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

The centromere region of the human ChrX is known as an area with extremely low crossing-over-rates. Since tightly linked and non-recombining STRs are required for kinship testing, we validated a cluster of six STRs for forensic use in this region, where stable haplotypes can be expected. Our multiplex PCR setup comprised the simultaneous amplification of the six markers DXS10161, DXS10159, DXS10162, DXS10163, DXS10164 and DXS10165, which are located between 56 and 64 Mb distanced from the Xp telomere at Xp11.21-Xq11.1. Differences between several populations are expected. We present allele- and haplotype-frequency data of population samples from Germany, Estonia, Latvia, Lithuania, Wroclaw, Vladivostok, Finland, Japan, Ethiopia and Rwanda. Our ChrX centromere multiplex is a suitable supplement of the commercially available ChrX-Kit Argus X12 and can be used as an additional independent haplogroup.

In this study a set of 29 X-chromosomal short tandem repeats (STRs) located within the Xq26 region was evaluated. These STRs were found within the 133.14–133.45Mb region around the HPRTB locus. Evaluation of the microsatellites was performed with regard to polymorphism, reliable amplification, and low stutter artefacts. DXS10101, DXS10102, and DXS10103 were identified as those X-STRs with highest diversity; i.e. PIC values of 0.7174–0.8933. The locus DXS10101 was the optimal candidate for the integration in the commercial available test system Mentype Argus X-8 PCR amplification kit.

We propose that clusters of closely linked markers, which segregate as stable haplotypes, provide a high potential to solve complex kinship cases. It is known that the X-chromosomal centromere region shows an extremely low degree of recombination. Hence, we focused our interest on the region between 56 and 64 Mb distant from the Xp telomere and considered 6 STRs which are now registered in the Genome Data Base as DXS10161, DXS10159, DXS10162, DXS10163, DXS10164, and DXS10165. All of these markers show a tetranucleotide or pentanucleotide structure and exhibit high or medium polymorphic information content. As a peculiarity, DXS10163 is a combination of a pentanucleotide STR and an 18 bp INDEL polymorphism. We report here the primer sequences, the repeat structures, the allele distributions and parameters of forensic interest for a German population sample.

Typing of polymorphisms on the human chromosome X (ChrX) has become a standard technique in forensic genetics, and a growing number of short tandem repeats (STRs) has been established. Knowledge of marker recombination is of great significance especially when ChrX typing is used in forensic kinship testing. It is known that meiotic recombination is not a simple function of physical distance but crossing over events tend to be clustered. Information on genetic distances between markers can be gathered by family studies and by interpolation of gene bank data such as the Rutgers map. We typed DNA samples of pedigrees consisting of mothers with several sons and grandfather–mother–son constellations and report here the recombination characteristics of 39 ChrX STRs in up to 135 meioses.

Insertion/deletion polymorphisms (indels) are diallelic markers which are underutilised in the forensic science. The simple structure of diallelic markers enables them to generate very short amplicons which facilitate successful typing of degraded DNA samples. Introducing indels into the ensemble of kinship testing tools we here present a panel of 26 X-chromosome indels, which can be amplified and analysed using 5 multiplex PCR setups.