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1.
Sci Justice ; 64(4): 389-396, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39025564

ABSTRACT

DNA technology is the gold standard with respect to the identification of individuals from biological evidence. The technology offers the convenience of a universally similar approach and methodology for analysis across the globe. However, the technology has not realised its full potential in India due to the lack of a DNA database and lacunae in sample collection and preservation from the scene of crime and victims (especially those of sexual assault). Further, statistical interpretation of DNA results is non-existent in the majority of cases. Though the latest technologies and developments in the field of DNA analysis are being adopted and implemented,very little has been enacted practically to improve optimise sample collection and preservation. This article discusses current casework scenarios that highlight the pitfalls and ambiguous areas in the field of DNA analysis, especially with respect DNA databases, sampling, andstatistical approaches to genetic data analysis. Possible solutions and mitigation measures are suggested.


Subject(s)
DNA Fingerprinting , Databases, Nucleic Acid , Specimen Handling , Humans , India , DNA Fingerprinting/methods , Specimen Handling/methods , Genetic Markers , Forensic Genetics/methods , DNA/analysis
2.
J Forensic Sci ; 69(4): 1125-1137, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38853374

ABSTRACT

The subject of inter- and intra-laboratory inconsistency was recently raised in a commentary by Itiel Dror. We re-visit an inter-laboratory trial, with which some of the authors of this current discussion were associated, to diagnose the causes of any differences in the likelihood ratios (LRs) assigned using probabilistic genotyping software. Some of the variation was due to different decisions that would be made on a case-by-case basis, some due to laboratory policy and would hence differ between laboratories, and the final and smallest part was the run-to-run difference caused by the Monte Carlo aspect of the software used. However, the net variation in LRs was considerable. We believe that most laboratories will self-diagnose the cause of their difference from the majority answer and in some, but not all instances will take corrective action. An inter-laboratory exercise consisting of raw data files for relatively straightforward mixtures, such as two mixtures of three or four persons, would allow laboratories to calibrate their procedures and findings.


Subject(s)
Software , Humans , Likelihood Functions , Monte Carlo Method , DNA Fingerprinting , Genotype , Laboratories/standards , Decision Making , Forensic Genetics/methods
3.
Sci Rep ; 14(1): 13271, 2024 06 10.
Article in English | MEDLINE | ID: mdl-38858407

ABSTRACT

Touch DNA, which can be found at crime scenes, consists of invisible biological traces deposited through a person's skin's contact with an object or another person. Many factors influence touch DNA transfer, including the "destination" substrate's surface. The latter's physicochemical characteristics (wettability, roughness, surface energy, etc.) will impact touch DNA deposition and persistence on a substrate. We selected a representative panel of substrates from objects found at crime scenes (glass, polystyrene, tiles, raw wood, etc.) to investigate the impact of these characteristics on touch DNA deposition and detection. These were shown to impact cell deposition, morphology, retention, and subsequent touch DNA genetic analysis. Interestingly, cell-derived fragments found within keratinocyte cells and fingermarks using in vitro touch DNA models could be successfully detected whichever the substrates' physicochemistry by targeting cellular proteins and carbohydrates for two months, indoors and outdoors. However, swabbing and genetic analyses of such mock traces from different substrates produced informative profiles mainly for substrates with the highest surface free energy and therefore the most hydrophilic. The substrates' intrinsic characteristics need to be considered to better understand both the transfer and persistence of biological traces, as well as their detection and collection, which require an appropriate methodology and sampling device to get informative genetic profiles.


Subject(s)
DNA , Touch , Humans , DNA/chemistry , Surface Properties , Skin/metabolism , Skin/chemistry , Keratinocytes/metabolism , DNA Fingerprinting/methods
4.
Genes (Basel) ; 15(6)2024 May 23.
Article in English | MEDLINE | ID: mdl-38927608

ABSTRACT

Bones and teeth represent a common finding in ancient DNA studies and in forensic casework, even after a long burial. Genetic typing is the gold standard for the personal identification of skeletal remains, but there are two main factors involved in the successful DNA typing of such samples: (1) the set-up of an efficient DNA extraction method; (2) the identification of the most suitable skeletal element for the downstream genetic analyses. In this paper, a protocol based on the processing of 0.5 g of bone powder decalcified using Na2EDTA proved to be suitable for a semi-automated DNA extraction workflow using the Maxwell® FSC DNA IQ™ Casework Kit (Promega, Madison, WI, USA). The performance of this method in terms of DNA recovery and quality was compared with a full demineralisation extraction protocol based on Qiagen technology and kits. No statistically significant differences were scored according to the DNA recovery and DNA degradation index (p-values ≥ 0.176; r ≥ 0.907). This new DNA extraction protocol was applied to 88 bone samples (41 femurs, 19 petrous bones, 12 metacarpals and 16 molars) allegedly belonging to 27 World War II Italian soldiers found in a mass grave on the isle of Cres (Croatia). The results of the qPCR performed by the Quantifiler Human DNA Quantification kit showed values above the lowest Limit of Quantification (lLOQ; 23 pg/µL) for all petrous bones, whereas other bone types showed, in most cases, lower amounts of DNA. Replicate STR-CE analyses showed successful typing (that is, >12 markers) in all tests on the petrous bones, followed by the metacarpals (83.3%), femurs (52.2%) and teeth (20.0%). Full profiles (22/22 autosomal markers) were achieved mainly in the petrous bones (84.2%), followed by the metacarpals (41.7%). Stochastic amplification artefacts such as drop-outs or drop-ins occurred with a frequency of 1.9% in the petrous bones, whereas they were higher when the DNA recovered from other bone elements was amplified (up to 13.9% in the femurs). Overall, the results of this study confirm that petrous bone outperforms other bone elements in terms of the quantity and quality of the recovered DNA; for this reason, if available, it should always be preferred for genetic testing. In addition, our results highlight the need for accurate planning of the DVI operation, which should be carried out by a multi-disciplinary team, and the tricky issue of identifying other suitable skeletal elements for genetic testing. Overall, the results presented in this paper support the need to adopt preanalytical strategies positively related to the successful genetic testing of aged skeletal remains in order to reduce costs and the time of analysis.


Subject(s)
Bone and Bones , Humans , Bone and Bones/chemistry , World War II , DNA Fingerprinting/methods , Forensic Genetics/methods , Microsatellite Repeats/genetics , DNA/genetics , DNA/isolation & purification , DNA, Ancient/analysis
5.
Genes (Basel) ; 15(6)2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38927680

ABSTRACT

DNA quantification is a crucial step in the STR typing workflow for human identification purposes. Given the reaction's nature, qPCR assays may be subjected to the same stochastic effects of traditional PCR for low-input concentrations. The study aims to evaluate the precision of the PowerQuant® (Promega) kit assay measurements and the degree of variability for DNA templates falling below the optimal threshold of the PowerPlex® ESX-17 Fast STR typing kit (Promega). Five three-fold dilutions of the 2800 M control DNA (Promega) were set up. Each dilution (concentrations: 0.05, 0.0167, 0.0055, 0.00185, and 0.000617 ng/µL) was quantified and amplified in four replicates. Variability for qPCR results, STR profile completeness, and EPGs' peak height were evaluated. The qPCR-estimated concentration of casework samples was correlated with profile completeness and peak intensity, to assess the predictive value of qPCR results for the successful STR typing of scarce samples. qPCR was subjected to stochastic effects, of which the degree was inversely proportional to the initial input template. Quantitation results and the STR profile's characteristics were strongly correlated. Due to the intrinsic nature of real casework samples, a qPCR-derived DNA concentration threshold for correctly identifying probative STR profiles may be difficult to establish. Quantitation data may be useful in interpreting and corroborating STR typing results and for clearly illustrating them to the stakeholders.


Subject(s)
Microsatellite Repeats , Real-Time Polymerase Chain Reaction , Humans , Microsatellite Repeats/genetics , Real-Time Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/standards , DNA Fingerprinting/methods , Forensic Genetics/methods , DNA/genetics
6.
Genes (Basel) ; 15(6)2024 Jun 09.
Article in English | MEDLINE | ID: mdl-38927695

ABSTRACT

The quantification of human DNA extracts from forensic samples plays a key role in the forensic genetics process, ensuring maximum efficiency and avoiding repeated analyses, over-amplified samples, or unnecessary examinations. In our laboratory, we use the Quantifiler® Trio system to quantify DNA extracts from a wide range of samples extracted from traces (bloodstains, saliva, semen, tissues, etc.), including swabs from touched objects, which are very numerous in the forensic context. This method has been extensively used continuously for nine years, following an initial validation process, and is part of the ISO/IEC 17025 accredited method. In routine practice, based on the quantitative values determined from the extracts of each trace, we use a standard method or a low-copy-number method that involves repeating the amplification with the generation of a consensus genetic profile. Nowadays, when the quantification results are less than 0.003 ng/µL in the minimum extraction volume (40 µL), we do not proceed with the DNA extract analysis. By verifying the limits of the method, we make a conscious cost-benefit choice, in particular by using the least amount of DNA needed to obtain sufficiently robust genetic profiles appropriate for submission to the Italian DNA Forensic Database. In this work, we present a critical re-evaluation of this phase of the method, which is based on the use of standard curves obtained from the average values of the control DNA analysed in duplicate. Considering the various contributions to uncertainty that are difficult to measure, such as manual pipetting or analytical phases carried out by different operators, we have decided to thoroughly investigate the contribution of variability in the preparation of calibration curves to the final results. Thus, 757 samples from 20 independent experiments were re-evaluated using two different standards for the construction of curves, determining the quantitative differences between the two methods. The experiments also determined the parameters of the slope, Y-intercept, R2, and the values of the synthetic control probe to verify how these parameters can provide information on the final outcome of each analysis. The outcome of this revalidation demonstrated that it is preferable to use quantification ranges rather than exact quantitative limits before deciding how to analyse the extracts via PCR or forgoing the determination of profiles. Additionally, we present some preliminary data related to the analysis of samples that would not have been analysed based on the initial validation, from which genetic profiles were obtained after applying a concentration method to the extracts. Our goal is to improve the accredited analytical method, with a careful risk assessment as indicated by accreditation standards, ensuring that no source of evidence is lost in the reconstruction of a criminal event.


Subject(s)
DNA , Forensic Genetics , Real-Time Polymerase Chain Reaction , Humans , Real-Time Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/standards , Forensic Genetics/methods , Forensic Genetics/standards , DNA/analysis , DNA/genetics , DNA Fingerprinting/methods , Microsatellite Repeats , Semen/chemistry
7.
Genes (Basel) ; 15(6)2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38927704

ABSTRACT

Although guidelines exist for identifying mixtures, these measures often occur at the end-point of analysis and are protracted. To facilitate early mixture detection, we integrated a high-resolution melt (HRM) mixture screening assay into the qPCR step of the forensic workflow, producing the integrated QuantifilerTM Trio-HRM assay. The assay, when coupled with a prediction tool, allowed for 75.0% accurate identification of the contributor status of a sample (single source vs. mixture). To elucidate the limitations of the developed qPCR-HRM assay, developmental validation studies were conducted assessing the reproducibility and samples with varying DNA ratios, contributors, and quality. From this work, it was determined that the integrated QuantifilerTM Trio-HRM assay is capable of accurately identifying mixtures with up to five contributors and mixtures at ratios up to 1:100. Further, the optimal performance concentration range was found to be between 0.025 and 0.5 ng/µL. With these results, evidentiary-like DNA samples were then analyzed, resulting in 100.0% of the mixture samples being accurately identified; furthermore, every time a sample was predicted as a single source, it was true, giving confidence to any single-source calls. Overall, the integrated QuantifilerTM Trio-HRM assay has exhibited an enhanced ability to discern mixture samples from single-source samples at the qPCR stage under commonly observed conditions regardless of the contributor's sex.


Subject(s)
Forensic Genetics , Humans , Forensic Genetics/methods , Real-Time Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/standards , DNA/genetics , DNA Fingerprinting/methods , Reproducibility of Results , Microsatellite Repeats/genetics
8.
Croat Med J ; 65(3): 249-260, 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38868971

ABSTRACT

The field of forensic DNA analysis has experienced significant advancements over the years, such as the advent of DNA fingerprinting, the introduction of the polymerase chain reaction for increased sensitivity, the shift to a primary genetic marker system based on short tandem repeats, and implementation of national DNA databases. Now, the forensics field is poised for another revolution with the advent of dense single nucleotide polymorphisms (SNPs) testing. SNP testing holds the potential to significantly enhance source attribution in forensic cases, particularly those involving low-quantity or low-quality samples. When coupled with genetic genealogy and kinship analysis, it can resolve countless active cases as well as cold cases and cases of unidentified human remains, which are hindered by the limitations of existing forensic capabilities that fail to generate viable investigative leads with DNA. The field of forensic genetic genealogy combined with genome-wide sequencing can associate relatives as distant as the seventh-degree and beyond. By leveraging volunteer-populated databases to locate near and distant relatives, genetic genealogy can effectively narrow the candidates linked to crime scene evidence or aid in determining the identity of human remains. With decreasing DNA sequencing costs and improving sensitivity of detection, forensic genetic genealogy is expanding its capabilities to generate investigative leads from a wide range of biological evidence.


Subject(s)
DNA Fingerprinting , Forensic Genetics , Polymorphism, Single Nucleotide , Humans , DNA Fingerprinting/methods , Forensic Genetics/methods , Pedigree
9.
Croat Med J ; 65(3): 239-248, 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38868970

ABSTRACT

Over the past 30 years, forensic experts from Croatia and Bosnia and Herzegovina have embraced advanced technologies and innovations to enable great efficacy and proficiency in the identification of war victims. The wartime events in the countries of former Yugoslavia greatly influenced the application of the selected DNA analyses as routine tools for the identification of skeletal remains, especially those from mass graves. Initially, the work was challenging because of the magnitude of the events, technical aspects, and political aspects. Collaboration with reputable foreign forensic experts helped tremendously in the efforts to start applying DNA analysis routinely and with increasing success. In this article, we reviewed the most significant achievements related to the application of DNA analysis in identifying skeletal remains in situations where standard identification methods were insufficient.


Subject(s)
Body Remains , Bosnia and Herzegovina , Humans , Croatia , Forensic Anthropology/methods , Warfare , DNA Fingerprinting
10.
Forensic Sci Int Genet ; 71: 103066, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38833776

ABSTRACT

In forensic practice, mixture stains containing various body fluids are common, presenting challenges for interpretation, particularly in multi-contributor mixtures. Traditional STR profiles face difficulties in such scenarios. Over recent years, RNA has emerged as a promising biomarker for body fluid identification, and mRNA polymorphism has shown excellent performance in identifying body fluid donors in previous studies. In this study, a massively parallel sequencing assay was developed, encompassing 202 coding region SNPs (cSNPs) from 45 body fluid/tissue-specific genes to identify both body fluid/tissue origin and the respective donors, including blood, saliva, semen, vaginal secretion, menstrual blood, and skin. The specificity was evaluated by examining the single-source body fluids/tissue and revealed that the same body fluid exhibited similar expression profiles and the tissue origin could be identified. For laboratory-generated mixtures containing 2-6 different components and mock case mixtures, the donor of each component could be successfully identified, except for the skin donor. The discriminatory power for all body fluids ranged from 0.997176329 (menstrual blood) to 0.99999999827 (blood). The concordance of DNA typing and mRNA typing for the cSNPs in this system was also validated. This cSNP typing system exhibits excellent performance in mixture deconvolution.


Subject(s)
Cervix Mucus , High-Throughput Nucleotide Sequencing , Polymorphism, Single Nucleotide , RNA, Messenger , Saliva , Semen , Humans , RNA, Messenger/genetics , Female , Semen/chemistry , Cervix Mucus/chemistry , Saliva/chemistry , Male , Body Fluids/chemistry , DNA Fingerprinting , Skin/chemistry , Menstruation , Forensic Genetics/methods , Tissue Donors , Sequence Analysis, RNA
11.
Forensic Sci Int Genet ; 71: 103064, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38833777

ABSTRACT

SE33 or ACTBP2 is the most polymorphic locus in many national DNA databases and in the commercial STR kits used to type both crime scene samples and reference samples to populate these databases. We describe the molecular reason for a three band pattern of SE33 seen in several samples. A SNP in the flanking SE33 region causes the binding of the unlabelled D3S1358 primer. As a result, a "chimeric" PCR product of the labelled SE33 primer and the D3S1358 primer is generated that is smaller than the regular SE33 amplicon. We call this "Type 3 three band pattern" as the genetic base differs from the Type 1 three band pattern caused by somatic mosaicism and the Type 2 that results from copy number variation.


Subject(s)
Microsatellite Repeats , Polymerase Chain Reaction , Humans , Polymorphism, Single Nucleotide , DNA Fingerprinting , DNA Primers , DNA Copy Number Variations
12.
Forensic Sci Int Genet ; 71: 103067, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38833778

ABSTRACT

Significant variation exists in the molecular structure of compact and trabecular bone. In compact bone full dissolution of the bone powder is required to efficiently release the DNA from hydroxyapatite. In trabecular bone where soft tissues are preserved, we assume that full dissolution of the bone powder is not required to release the DNA from collagen. To investigate this issue, research was performed on 45 Second World War diaphysis (compact bone)-epiphysis (trabecular bone) femur pairs, each processed with a full dissolution (FD) and partial dissolution (PD) extraction method. DNA quality and quantity were assessed using qPCR PowerQuant analyses, and autosomal STRs were typed to confirm the authenticity of isolated DNA. Our results support different mechanisms of DNA preservation in compact and trabecular bone because FD method was more efficient than PD method only in compact bone, and no difference in DNA yield was observed in trabecular bone, showing no need for full dissolution of the bone powder when trabecular bone tissue is processed. In addition, a significant difference in DNA yield was observed between compact and trabecular bone when PD was applied, with more DNA extracted from trabecular bone than compact bone. High suitability of trabecular bone processed with PD method is also supported by the similar quantities of DNA isolated by FD method when applied to both compact and trabecular bone. Additionally similar quantities of DNA were isolated when compact bone was extracted with FD method and trabecular bone was extracted with PD method. Processing trabecular bone with PD method in routine identification of skeletonized human remains shortens the extraction procedure and simplifies the grinding process.


Subject(s)
Cancellous Bone , DNA , Femur , Microsatellite Repeats , Humans , DNA/genetics , Femur/chemistry , DNA Fingerprinting , Polymerase Chain Reaction , Male , Real-Time Polymerase Chain Reaction
13.
Genes (Basel) ; 15(5)2024 05 14.
Article in English | MEDLINE | ID: mdl-38790251

ABSTRACT

The assessment of degradation is crucial for the analysis of human DNA samples isolated from forensic specimens. Forensic quantitative PCR (qPCR) assays can include multiple targets of varying amplicon size that display differential amplification efficiency, and thus different concentrations, in the presence of degradation. The possibility of deriving information on DNA degradation was evaluated in a forensic qPCR assay not specifically designed to detect DNA fragmentation, the Plexor HY (Promega), by calculating the ratio between the estimated concentrations of autosomal (99 bp) and Y-chromosomal (133 bp) targets ("[Auto]/[Y]"). The [Auto]/[Y] ratio measured in 57 formalin-fixed, paraffin-embedded samples was compared to a quality score (QS) calculated for corresponding STR profiles using quantitative data (allele peak height). A statistically significant inverse correlation was observed between [Auto]/[Y] and QS (R = -0.65, p < 0.001). The [Auto]/[Y] values were highly correlated (R = 0.75, p < 0.001) with the "[Auto]/[D]" values obtained using the PowerQuant (Promega) assay, expressly designed to detect DNA degradation through simultaneous quantification of a short (Auto) and a long (D) autosomal target. These results indicate that it is possible to estimate DNA degradation in male samples through Plexor HY data and suggest an alternative strategy for laboratories lacking the equipment required for the assessment of DNA integrity through dedicated qPCR assays.


Subject(s)
Chromosomes, Human, Y , DNA , Real-Time Polymerase Chain Reaction , Humans , Male , DNA/genetics , Chromosomes, Human, Y/genetics , Real-Time Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/standards , Forensic Genetics/methods , Microsatellite Repeats/genetics , DNA Degradation, Necrotic , DNA Fragmentation , DNA Fingerprinting/methods
14.
Forensic Sci Int ; 360: 112064, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38805773

ABSTRACT

The generation of high-quality DNA profiles from trace amounts of DNA continues to be an issue in forensic casework. Several methods have been proposed over the years to increase recovery rates for low input DNA, including purification of PCR products, an increase in PCR cycle numbers and increasing injection time or voltage during electrophoresis. In this study, the characteristics of DNA profiles generated using QIAGEN MinElute® purification of Promega PowerPlex® 21 amplified products for low DNA input samples, ranging from 80 pg down to 4 pg, were evaluated. MinElute® purification was found to be a simple, effective and time efficient method, which can greatly improve the resolution of amplified PCR products, recovering 100% of donor concordant alleles from as little 16 pg of input template DNA and generating sufficient allelic information for interpretation from as low as 4 pg inputs. However, as is commonly observed with low template DNA samples, the results exhibited extensive disparity in the effects of stochastic variation in amplification, including increased heterozygote peak height imbalance, stutter ratios and instances of allelic drop-in and drop-out, both within and between replicates. As such, it is important that the extent and variability of these stochastic effects are appropriately incorporated in the development of robust profile interpretation guidelines for DNA profiles generated from purified PCR products.


Subject(s)
DNA Fingerprinting , DNA , Microsatellite Repeats , Polymerase Chain Reaction , DNA Fingerprinting/methods , Humans , DNA/isolation & purification , Alleles
15.
Forensic Sci Int ; 360: 112076, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38821024

ABSTRACT

A comparative analysis of 26 petrous bones and epiphyses of metacarpals from the Second World War era revealed no significant differences in DNA yield or success in STR typing. This unexpected parity in DNA preservation between the petrous bone, a renowned source of endogenous DNA in skeletal remains, and the epiphyses of metacarpals, which are porous and susceptible to taphonomic changes, is surprising. In this study, we introduced ATR-FTIR spectroscopy as an approach to unravel the correlation between bone molecular structure and DNA preservation. Metacarpals and petrous bones with same taphonomic history were sampled and prepared for DNA analyses. While one portion of the sample was used for DNA analysis, the other underwent ATR-FTIR spectroscopic examination. The normalized spectra and FTIR indices between the epiphyses of metacarpals and petrous bones were compared. Because the taphonomic history of the remains used is relatively short and stable, the ATR-FTIR spectroscopy unveiled subtle structural differences between the two bone types. Petrous bones exhibited higher mineralization, whereas epiphyses contained more organic matter. The unexpected preservation of DNA in the epiphyses of metacarpals can likely be attributed to the presence of soft tissue remnants within the trabeculae. Here observed differences in the molecular structure of bones indicate there are different mechanisms enabling DNA preservation in skeletal tissues.


Subject(s)
DNA , Epiphyses , Metacarpal Bones , Petrous Bone , Humans , Spectroscopy, Fourier Transform Infrared , Petrous Bone/chemistry , Epiphyses/chemistry , Metacarpal Bones/chemistry , DNA Fingerprinting/methods , Microsatellite Repeats , World War II
16.
J Forensic Sci ; 69(4): 1481-1489, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38703136

ABSTRACT

The potential evidential value of male underwear in cases of alleged sexual assault is often overlooked. Male underwear can be a critical item in the investigation of alleged sexual assaults. Body fluids/DNA, which may transfer to the penis during sexual contact, may in turn transfer to the inside front of the underwear, and persist for months or years, provided the underwear are not washed. Here, we demonstrate how the case circumstances drive the sampling strategy of male underwear, in order to maximize the effectiveness of the forensic analysis. Sampling considerations including recovery methods and sampling sequence are discussed, and a methodical examination strategy of male underwear is proposed. To highlight the pertinence of male underwear to the investigation of alleged sexual assaults, three real-life cases are discussed, in which male underwear were examined for multiple body fluids/DNA, and the findings obtained proved evidentially significant. The different cases demonstrate the versatility of male underwear examination in situations, where different body fluids and DNA may transfer based on the specific allegation, and emphasize how targeted sampling can allow the scientist to assess the probability of the findings based on two competing propositions. Accurate sampling strategies are imperative for robust probability assignment in evaluative reporting of scientific findings.


Subject(s)
Clothing , DNA , Specimen Handling , Humans , Male , DNA/analysis , DNA/isolation & purification , Adult , DNA Fingerprinting , Sex Offenses , Female , Semen/chemistry , Cervix Mucus/chemistry , Polymerase Chain Reaction , Young Adult
17.
Forensic Sci Int ; 360: 112043, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38705055

ABSTRACT

Weak and partial DNA profiles are commonly encountered within forensic casework due to amplification of low DNA input samples. One option for increasing allelic detection in such samples is the purification of amplified PCR product using commercially available column-based methods. In this study, four commercially available post-PCR purification methods, QIAGEN MinElute®, Independent Forensics Amplicon™ Rx, Millipore Microcon® and Thermo Fisher Scientific ExoSAP-IT™ were evaluated, comparing the quality of PowerPlex® 21 DNA profiles produced to the standard DNA profile generated prior to purification. An increased detection of alleles above the analytical threshold was observed following purification with the MinElute®, Amplicon™ Rx and Microcon® methods, allowing informative DNA profiles to be recovered using as little as 8 pg DNA. However, post-PCR purification using the ExoSAP-IT™ kit was unsuccessful, with no alleles detected above analytical threshold in samples with ≤16 pg DNA. The MinElute® kit was selected for optimisation on the basis of DNA profile quality, including increased detection of alleles and minimal artefacts. The MinElute® method was optimised by evaluating the number of washes and final elution buffer volume, resulting in a further increase in detection of alleles by reducing the elution buffer volume. Overall, this study showed that PowerPlex® 21 DNA profiles from low input DNA can be successfully enhanced by employing the MinElute® post-PCR purification method.


Subject(s)
DNA Fingerprinting , DNA , Microsatellite Repeats , Polymerase Chain Reaction , Humans , DNA Fingerprinting/methods , Polymerase Chain Reaction/methods , DNA/isolation & purification , Alleles
18.
Forensic Sci Int ; 360: 112046, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38718526

ABSTRACT

Research into the recovery of DNA from illicit drug samples has shown it is possible to get forensically useful profiles from such substrates. However, it is not yet known if the different physical states that drugs can be found in influences the quantity and quality of DNA that can be recovered or what is the best sampling method to adopt for powdered samples. This research used acetaminophen in four different states - large crystalline, powder, in solution, or residue - to determine the efficacy of current DNA technology in recovery and analysis of the resulting sample. Five replicates of each were prepared. Human blood was deposited on or mixed with the drug and left for 1 hour. The surface of the drug was sampled by wet/dry swabbing (where appropriate), or the entire sample was deposited in a tube, and the DNA then extracted using DNA-IQ™. The amount of DNA recovered (ng), degradation index, number of PCR cycles (Ct) required for the IPC to reach threshold, number of alleles in the DNA profile and average peak height (APH) were assessed. All samples, irrespective of the physical state they were collected from, returned full DNA profiles that corresponded to the DNA profile of the blood donor, with no degradation or inhibition detected. It was also found the wet/dry swabbing method returned higher levels of DNA than inclusion of the entire sample into the tube for powdered acetaminophen and the appropriate method to use will be dependent on casework circumstances. The findings of this research further develops our understanding of the recovery of DNA from drugs, and supports the need for further investigation to understand under what conditions DNA can be recovered from illicit substances.


Subject(s)
Acetaminophen , DNA Fingerprinting , DNA , Polymerase Chain Reaction , Specimen Handling , Acetaminophen/blood , Humans , DNA/isolation & purification , Specimen Handling/methods , DNA Fingerprinting/methods , Powders , Microsatellite Repeats , Analgesics, Non-Narcotic , DNA Degradation, Necrotic
19.
Zhongguo Zhong Yao Za Zhi ; 49(7): 1826-1833, 2024 Apr.
Article in Chinese | MEDLINE | ID: mdl-38812195

ABSTRACT

Whether adulteration exists is a difficult problem in the identification of traditional Chinese medicine(TCM). Bubali Cornu is mainly available in the medicinal material market in the form of buffalo horn silk or buffalo horn powder but lacks obvious identification characteristics, so there is a risk of adulteration. However, the method of identification of adulteration in Bubali Cornu is lacking at present. In order to ensure authenticity and identify adulteration of TCM Bubali Cornu, control the quality of TCM Bubali Cornu, and ensure the authenticity of clinical use, the DNA fingerprints of 43 batches of samples from pharmaceutical companies and medicinal material markets were identified, and the amplification primers of fluorescent DNA fingerprints of Bubali Cornu and Bovis Grunniens Cornu were screened. The DNA fingerprints of Bubali Cornu were obtained by fluorescent capillary typing. The identification effect of fluorescent capillary typing on different adulteration ratios was also tested. Two pairs of fluorescent STR typing primers, namely 16Sa and CRc, which can distinguish Bubali Cornu and Bovis Grunniens Cornu, were screened out, and a DNA fingerprint identification method was established. The 16Sa migration peaks of Bovis Grunniens Cornu and Bubali Cornu were 223.4-223.9 bp and 225.5-226.1 bp. The CRc migration peaks of Bovis Grunniens Cornu and Bubali Cornu were 518.8-524.8 bp and 535.9-542.5 bp. The peak height of the migration peak could be used for preliminary quantification of the adulterants with an adulteration ratio below 50%, and the quantitative results were similar to the adulteration ratio. In this study, a simple and quick universal DNA fingerprint method was established for the identification of Bubali Cornu and its adulterants, which could realize the identification of TCM Bubali Cornu and the semi-quantitative identification of the adulterants.


Subject(s)
Buffaloes , DNA Fingerprinting , Drug Contamination , DNA Fingerprinting/methods , Animals , Buffaloes/genetics , Medicine, Chinese Traditional , Horns , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/analysis
20.
Forensic Sci Int Genet ; 71: 103053, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38728819

ABSTRACT

The Forensic Databases Advisory Board (FDAB), an independent board that assists the International Society for Forensic Genetics (ISFG), has presented a First Report on ethical aspects of the following Forensic Genetic Frequency Databases (FGFD): EMPOP, STRidER and YHRD. The FDAB designed an ethical framework to evaluate the content of these FGFD, and the factors to be considered for retention and acceptance of submissions. The FDAB framework proposes to categorize submissions according to the risk of having contravened the universal ethical principles outlined by international organizations, and the guidelines adopted by the ISFG. The report has been open to discussion by the scientific community since 2023. Herein we present the conception and development of the First Report along with a summary of its content, with consideration of the feedback received.


Subject(s)
Forensic Genetics , Humans , Forensic Genetics/ethics , Gene Frequency , Databases, Genetic , Databases, Nucleic Acid/ethics , DNA Fingerprinting/ethics
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