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1.
Int J Mol Sci ; 24(4)2023 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-36834791

RESUMEN

Forensic DNA profiles are established by multiplex PCR amplification of a set of highly variable short tandem repeat (STR) loci followed by capillary electrophoresis (CE) as a means to assign alleles to PCR products of differential length. Recently, CE analysis of STR amplicons has been supplemented by high-throughput next generation sequencing (NGS) techniques that are able to detect isoalleles bearing sequence polymorphisms and allow for an improved analysis of degraded DNA. Several such assays have been commercialised and validated for forensic applications. However, these systems are cost-effective only when applied to high numbers of samples. We report here an alternative, cost-efficient shallow-sequence output NGS assay called maSTR assay that, in conjunction with a dedicated bioinformatics pipeline called SNiPSTR, can be implemented with standard NGS instrumentation. In a back-to-back comparison with a CE-based, commercial forensic STR kit, we find that for samples with low DNA content, with mixed DNA from different individuals, or containing PCR inhibitors, the maSTR assay performs equally well, and with degraded DNA is superior to CE-based analysis. Thus, the maSTR assay is a simple, robust and cost-efficient NGS-based STR typing method applicable for human identification in forensic and biomedical contexts.


Asunto(s)
Dermatoglifia del ADN , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Dermatoglifia del ADN/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Análisis Costo-Beneficio , Repeticiones de Microsatélite , ADN/genética , Reacción en Cadena de la Polimerasa Multiplex , Análisis de Secuencia de ADN
2.
Anim Genet ; 52(5): 675-682, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34143521

RESUMEN

The domestic cat (Felis silvestris catus) is a valued companion animal throughout the world. Over 60 different cat breeds are accepted for competition by the cat fancy registries in different countries. Genetic markers, including short tandem repeats and SNPs, are available to evaluate and manage levels of inbreeding and genetic diversity, population and breed structure relationships, and individual identification for forensic and registration purposes. The International Society of Animal Genetics (ISAG) hosts the Applied Genetics in Companion Animals Workshop, which supports the standardization of genetic marker panels and genotyping for the identification of cats via comparison testing. SNP panels have been in development for many species, including the domestic cat. An ISAG approved core panel of SNPs for use in cat identification and parentage analyses is presented. SNPs (n = 121) were evaluated by different university-based and commercial laboratories using 20 DNA samples as part of the ISAG comparison testing procedures. Different SNP genotyping technologies were examined, including DNA arrays, genotyping-by-sequencing and mass spectroscopy, to select a robust and efficient panel of 101 SNPs as the ISAG core panel for cats. The SNPs are distributed across all chromosomes including two on the X chromosome and an XY pseudo-autosomal sexing marker (zinc-finger XY; ZFXY). A population study demonstrated that the markers have an average polymorphic information content of 0.354 and a power of exclusion greater than 0.9999. The SNP panel should keep testing affordable while also allowing for the development of additional panels to monitor health, phenotypic traits, hybrid cats and highly inbred cats.


Asunto(s)
Gatos/genética , Marcadores Genéticos , Técnicas de Genotipaje , Polimorfismo de Nucleótido Simple , Animales , Cruzamiento , Genética de Población , Técnicas de Genotipaje/normas , Análisis de Secuencia por Matrices de Oligonucleótidos/normas
3.
Anim Genet ; 51(4): 631-633, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32452546

RESUMEN

In dogs and cats, unusual coat colour phenotypes may result from various phenomena, including chimerism. In the domestic cat, the tortoiseshell coat colour that combines red and non-red hairs is the most obvious way to identify chimeras in males. Several cases of tortoiseshell males have been reported, some of which were diagnosed as chimeras without any molecular confirmation. Here, we report the case of a female feline chimera identified thanks to its coat colour and confirmed through DNA profiling and a coat colour test. We ruled out the hypothesis of mosaicism and aneuploidy. All the data were consistent with a natural case of female chimerism.


Asunto(s)
Gatos/genética , Quimerismo/veterinaria , Cabello/fisiología , Animales , Color , Dermatoglifia del ADN/veterinaria , Femenino , Pigmentación/genética
4.
Physiol Mol Biol Plants ; 26(2): 289-303, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32158136

RESUMEN

The purpose of this research by the way of investigating the molecular genetic structure of a highly variable fungal phytopathogen Pyricularia oryzae Cav., to determine effective genes for the development of a strategy for immunogenetic protection against rice blast in conditions of epiphytotic development of the disease in the south of Russia, which would combine high efficacy with both environmental friendliness and resource and energy saving, to ensure country's food security. The knowledge of local pathotype diversity of Pyricularia oryzae Cav. and the (a)virulence genes in rice-growing regions of Russia may allow the prediction of new races and its interaction in local agro-ecology. The identification of virulence gene may become an indispensable theoretical basis for the development of genetic sources with long-lasting resistance to rice blast. Based on molecular and genetic approaches, the genetic structure and biodiversity of the phytopathogenic fungus Pyricularia oryzae Cav. in the south of Russia were considered. The monitoring was studied and it isolated 57 strains of the pathogen from the damaged herbal material collected from the fields in eight agro-ecological rice-growing regions of the Krasnodar Region (Russian Federation): Krasnoarmeysky, Kalininsky, Krymsky, Abinsky, Temryuksky, Seversky, Slavyansky districts, Krasnodar, Rostov Region (Russian Federation)-Proletarsky district and the Republic of Adygea (Russian Federation). A multiplex PCR technique was applied on the basis of fragment analysis to identify the virulent fungal isolates. 33 fungal genotypes with unique genetic profiles were identified among the studied races of Pyricularia oryzae Cav. Their DNA profiles were created. The studied isolates of the pathogen of rice blast were classified using morphological and microbiology cultural features. Based on the phytopathological test using differentiation rice varieties, the quantitative and qualitative composition of (a)virulence genes in fungal races was established. Effective genes for pathogen resistance, which are recommended for breeding programs for the development of rice varieties resistant to rice blast, were identified in the south of Russia.

5.
Ann Hum Genet ; 83(2): 82-85, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30565662

RESUMEN

Population representative short tandem repeat (STR) allele frequencies are crucial for proper probabilistic interpretation of DNA forensic evidence. STR allele frequencies also provide information about the genetic diversity of a given population. The Lebanese population is characterized by the presence of more than 18 religious communities that have high recorded rates of endogamous and consanguineous marriages, where the choice of marriages is mainly influenced by their respective geographical distributions and religious affiliation. These factors could have led to an increase in complex DNA cases, whereby high numbers of STR markers are needed to help clear the case. Allele frequencies for 23 STR loci in the Lebanese population were recently estimated and published. The present study aims at estimating the STR allele frequencies for five supplementary STRs, namely, the LPL, F13B, FESFPS, F13A01, and Penta C STR markers, which are mainly used to resolve complex kinship investigations. A DNA database representative of the Lebanese population that comprises 505 Lebanese unrelated individuals was used to amplify the five STR systems, using the CS7 kit released by Promega. The allele frequencies for these STR systems were estimated, and a significant departure from the Hardy-Weinberg equilibrium was detected after Bonferroni correction for multiple tests at locus LPL, F13A01, and Penta C. The newly added systems appeared to have variation in their discriminative power among Lebanese individuals. Penta C showed the highest power of discrimination, whereas FESFPS showed the lowest power of discrimination. The estimated frequencies and population data could provide local DNA relationship testing laboratories with additional tools that help resolve complex DNA cases.


Asunto(s)
Frecuencia de los Genes , Variación Genética , Genética de Población , Repeticiones de Microsatélite , Humanos , Líbano
6.
Int J Legal Med ; 133(2): 433-463, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29627917

RESUMEN

Population allele frequency is an indicator of population genetic diversity and plays significant roles in DNA profiling interpretation in human identification, kinship, and forensic testing. The Lebanese population is a mosaic of 18 religious communities with high rates of consanguinity and endogamy. Allele frequencies for 23 STR loci were estimated and analyzed in the seven major Lebanese religious subcommunities (Muslims Shiaa, Sunni, and Druze, and Christians Orthodox, Maronite, and Catholics), to assess possible significant differences among their STR allele frequencies.


Asunto(s)
Etnicidad/genética , Variación Genética , Genética de Población , Repeticiones de Microsatélite , Dermatoglifia del ADN , Frecuencia de los Genes , Humanos , Líbano , Reacción en Cadena de la Polimerasa
7.
Sci Justice ; 57(1): 28-34, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28063582

RESUMEN

In this article we present the results of a study to explore if cross-border DNA matches between the Netherlands and Belgium are relatively more likely to occur in areas near the Dutch-Belgian border than in areas at some distance from this border. For this study we used the results of the transnational DNA profile exchange and comparison between the Belgian and Dutch DNA databases, which first took place in 2014. It appears that the Dutch regions adjacent to Belgium, i.e., Zeeland-West-Brabant, Oost-Brabant and Limburg, have relatively more DNA matches with Belgium than the other Dutch regions. In other words, a DNA profile obtained from a crime scene close to the Dutch border with Belgium is more likely to match with the profile of a person whose DNA profile is stored in the Belgian database than a DNA profile that originates from a crime scene further afield. Our data suggest that crimes committed by repeat offenders show a spatial pattern despite the presence of a national border, with crime scenes clustering in relatively close proximity to each other. The results of this study provide a better understanding of geographical patterns of cross-border criminal mobility.


Asunto(s)
Dermatoglifia del ADN , Bases de Datos de Ácidos Nucleicos , Bélgica , Crimen , Humanos , Países Bajos
8.
Int J Legal Med ; 130(3): 607-13, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26530406

RESUMEN

Disaster victim identification (DVI) often occurs in remote locations with extremes of temperatures and humidities. Access to mortuary facilities and refrigeration are not always available. An effective and robust DNA sampling and preservation procedure would increase the probability of successful DNA profiling and allow faster repatriation of bodies and body parts. If the act of tissue preservation also released DNA into solution, ready for polymerase chain reaction (PCR), the DVI process could be further streamlined. In this study, we explored the possibility of obtaining DNA profiles without DNA extraction, by adding aliquots of preservative solutions surrounding fresh human muscle and decomposing human muscle and skin tissue samples directly to PCR. The preservatives consisted of two custom preparations and two proprietary solutions. The custom preparations were a salt-saturated solution of dimethyl sulfoxide (DMSO) with ethylenediaminetetraacetic (EDTA) and TENT buffer (Tris, EDTA, NaCl, Tween 20). The proprietary preservatives were DNAgard (Biomatrica(®)) and Tissue Stabilising Kit (DNA Genotek). We obtained full PowerPlex(®) 21 (Promega) and GlobalFiler(®) (Life Technologies) DNA profiles from fresh and decomposed tissue preserved at 35 °C for up to 28 days for all four preservatives. The preservative aliquots removed from the fresh muscle tissue samples had been stored at -80 °C for 4 years, indicating that long-term archival does not diminish the probability of successful DNA typing. Rather, storage at -80 °C seems to reduce PCR inhibition.


Asunto(s)
Dermatoglifia del ADN/métodos , ADN/análisis , Reacción en Cadena de la Polimerasa , Conservación de Tejido , Crioprotectores , Dimetilsulfóxido , Ácido Edético , Genotipo , Humanos , Repeticiones de Microsatélite , Músculo Esquelético/química , Piel/química , Manejo de Especímenes/métodos
9.
Forensic Sci Int ; 355: 111944, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38277913

RESUMEN

Evaluations of forensic observations considering activity level propositions are becoming more common place in forensic institutions. A measure that can be taken to interrogate the evaluation for robustness is called sensitivity analysis. A sensitivity analysis explores the sensitivity of the evaluation to the data used when assigning probabilities, or to the level of uncertainty surrounding a probability assignment, or to the choice of various assumptions within the model. There have been a number of publications that describe sensitivity analysis in technical terms, and demonstrate their use, but limited literature on how that theory can be applied in practice. In this work we provide some simplified examples of how sensitivity analyses can be carried out, when they are likely to show that the evaluation is sensitive to underlying data, knowledge or assumptions, how to interpret the results of sensitivity analysis, and how the outcome can be reported. We also provide access to an application to conduct sensitivity analysis.


Asunto(s)
Teorema de Bayes , Incertidumbre
10.
Mol Genet Genomic Med ; 11(4): e2118, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36655620

RESUMEN

BACKGROUND: Understanding the genetic substructure of a population is essential for proper forensic genetic analysis. The Lebanese population has a high rate of endogamous and consanguineous marriages and is segregated based on religious belongings. However, no genetic population studies have been performed up to date to estimate the degree of genetic substructure and inbreeding coefficients. METHODS: The present study analyzed a compendium of 23 autosomal STRs typed in 1400 individuals belonging to the seven major Lebanese religious subcommunities. Inbreeding coefficients such as F statistics were estimated. RESULTS: Results showed a Fst (theta) value of 0.002, indicating a low genetic subdivision within the Lebanese population. CONCLUSION: This study aimed at assessing the genetic substructure of the Lebanese population by analyzing 1400 Lebanese citizens' samples using 23 STR markers. F statistics were computed to evaluate the degree of genetic substructure. Results showed a Fst value of 0.002, indicating a low genetic subdivision within the Lebanese population.


Asunto(s)
Genética de Población , Repeticiones de Microsatélite , Humanos , Frecuencia de los Genes , Consanguinidad , Proyectos de Investigación
11.
Forensic Sci Int Genet ; 64: 102830, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36702080

RESUMEN

Touch DNA recovery techniques can have limitations, as their effectiveness depends on the substrate on which the DNA of a person of interest can be found. In this study, an in-house dry-vacuuming device, the DNA-Buster, was compared to traditional methods for its DNA recovery performance from items typically examined in forensic casework. The aim was to evaluate whether this dry-vacuuming approach can recover DNA efficiently, potentially complementing the well-established recovery strategies. For this, the performances of swabbing, taping, wet- (M-Vac®) and dry-vacuuming (DNA-Buster) were investigated quantitatively and qualitatively for touch DNA deposited on carpet, cotton sweater, stone, tile and wood. For the sweater, both vacuuming methods outperformed the other collection tools quantitatively. While the highest DNA amounts for the carpet were yielded by swabbing and taping, dry-vacuuming was equally good in reaching full DNA profiles, whereas less complete profiles were observed for the M-Vac®. For stone and tile, swabbing was optimal, whereas dry-vacuuming clearly underperformed for these substrates. Taping was the best recovery method for wood. Despite applying single donor DNA after thoroughly cleaning the items, undesired DNA mixtures were detected for all recovery techniques and all substrates. The overall research findings show first that the novel dry-vacuuming method is suited for DNA recovery from textiles. Secondly, they indicate that more attention should be paid to the substrate-collection dependency to ensure best practices in recovering genetic material in a precise, confident and targeted manner from the variety of forensic casework material.


Asunto(s)
Pisos y Cubiertas de Piso , Tacto , Humanos , ADN/genética , Medicina Legal , Genética Forense/métodos , Dermatoglifia del ADN/métodos , Manejo de Especímenes/métodos
12.
Forensic Sci Int Genet ; 67: 102939, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37778314

RESUMEN

Employed for the first time in 1986, DNA profiling is nowadays established as one of the most widely used forensic techniques worldwide. However, until today, no efficient sampling technique existed to collect DNA from human skin cells from a large area, not to say from the floor of an entire room. This has been extremely unfortunate, as there is enormous forensic potential in these DNA traces from the ground to provide clues as to who has been present at a particular location, i.e. at the crime scene. By desquamation, humans loose several millions of skin cells per day, everywhere they stand, sit or walk; and they can do little about it. We developed a fast and simple method by which we can make use of all those lost skin cells. We use a vacuum cleaner equipped with a specialized filter cartridge to sample the ground. Fragmentation of the filter membrane and subsequent parallel processing of the filter fragments, using a modified Chelex® 100 extraction protocol, significantly reduce the complexity of the dust mixture. In this way, a large number of interpretable major contributor DNA profiles can be generated from individuals who have been present on the sampled surface. Overall, at least 38 % of the generated DNA profiles from all sampled test areas fulfilled the criteria for submission of single major contributor profiles to the Swiss DNA database. As demonstrated through a mock crime scene scenario simulating an indoor stabbing event, the perpetrator's DNA could be found on the floor even after a very short stay in the room of less than one minute. Furthermore, already the first application of the method at a real crime scene led to relevant case information for the police. Given its large investigative potential, we recommend Total Human DNA Sampling as a helpful complemental forensic tool to conventional DNA trace collection in major crimes.


Asunto(s)
Dermatoglifia del ADN , Bases de Datos de Ácidos Nucleicos , Humanos , Dermatoglifia del ADN/métodos , Manejo de Especímenes , ADN/genética , Crimen
13.
Forensic Sci Int Genet ; 65: 102873, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37094516

RESUMEN

Touch DNA recovery from firearms can be central to many criminal investigations, yet the generation of DNA profiles from these items remains poor. Currently in Australia, published casework data highlights extremely poor DNA success from samples recovered from firearms. Only between 5% and 25% of samples result in useful DNA data and therefore increasing the success of DNA recovered from firearms is highly important but has not yet been explored in-depth. This study focused on increasing the recovery of DNA from ten firearm components that were held for 15 s. Multiple recovery methods were used, and the resulting genetic data compared. DNA evidence may be deliberately removed from firearms after discharge to hamper forensic investigations, therefore this study examined the effect of wiping down the components or handling them with gloves. A standard double swab and rinse swab recovery method resulted in an average of 73% cellular recovery. A cumulative swab process had the highest average recovery at 86%, although it was found that increasing the DNA yield led to an increase in mixture complexity. Wiping over the components was observed to remove on average 69% of cellular material, compared with 33% when handed with gloves. However, the size and texture of the components affected the efficiency of cellular material removal. The results from this study allow for prioritisation of areas to sample on firearms, as well as suggesting techniques that can be applied for the optimum process of cellular recovery and subsequent generation of STR DNA data.


Asunto(s)
Armas de Fuego , Humanos , Dermatoglifia del ADN/métodos , Repeticiones de Microsatélite , ADN/genética , Tacto , Manejo de Especímenes/métodos
14.
J Forensic Sci ; 67(3): 1233-1240, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34978082

RESUMEN

Rapid DNA technology is being utilized for reference profiles worldwide. There is also strong data in the literature to support its use for high-template DNA sources, the same is not true for low-template sources, such as touch DNA; this is a requirement before wider implementation to forensic casework is considered. We report on the Rapid HIT Intel cartridge's ability to facilitate successful amplification of touch DNA to obtain profiles from template deposited on items commonly encountered in forensic casework. Eight items were touched in ten replicates- two were tapelifted, three swabbed, and three directly inserted. Significance was observed in the alleles amplified and RFU with respect to sample type. Three samples performed well: cable tie, fabric, and matchstick. As two of these were directly inserted, this should be considered for any sample small enough. Placement of highly absorbent substrates into the cartridge is not advised as it can cause a lysate-pull error. Heterozygote loci often presented as homozygous (32%-78% loci per profile); this was influenced by substrate type and profile RFU. Loci with larger masses exhibited higher false homozygosity also. Comparison of the donor's profile analyzed was performed against previous datasets analyzing touch DNA through standard workflow, including manual DNA extraction, PCR, and CE separation. These data show that for all substrates, except for a fabric swatch, standard processing is preferential to Rapid HIT analysis. In its current form, rapid DNA technology is not fit for the routine analysis of touch DNA samples in forensic casework.


Asunto(s)
Dermatoglifia del ADN , Tacto , ADN/análisis , Dermatoglifia del ADN/métodos , Genética Forense/métodos , Repeticiones de Microsatélite
15.
Forensic Sci Int Genet ; 58: 102683, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35240460

RESUMEN

Touch DNA is pivotal in forensic science therefore understanding the mechanisms and variations of deposition and composition of genetic material in touched deposits is essential. Shedder status is still poorly understood, and the consistency and cohesiveness of research is less developed compared to other transfer and persistence considerations. In this study, the inter- and intra-variations between shedder categories and individuals were investigated by use of a nucleic acid binding dye. Ten volunteers deposited 30 thumbprints under two different time points post handwashing: 15 after a period of 15 min post handwashing (defined) and 15 after a period of at least 60 min post handwashing (undefined). Thumbprints were made on glass slides, marked with a grid of 55 squares, then the marks were stained with Diamond Dye and the cells that fluoresced in each square (7500 total) counted to determine the total number of cells. Shedders were less consistent in cellular deposition when thumbprints were made in the defined condition compared to waiting at least 60 min. Heavy shedders consistently generated informative profiles (defined here as 12 or more alleles); this occurred 73% of the time in the defined condition and 87% in the undefined. Intermediate shedders produced informative profiles, which occurred 50% of the time in the defined and 80% in the undefined condition. Light shedders consistently produced uninformative profiles with only 33% being considered uploadable to a DNA database for the defined condition and 27% informative for the undefined condition.


Asunto(s)
Dermatoglifia del ADN , ADN , ADN/genética , Ciencias Forenses , Humanos , Repeticiones de Microsatélite , Reproducibilidad de los Resultados , Tacto
16.
Antibiotics (Basel) ; 11(7)2022 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-35884089

RESUMEN

Acinetobacter baumannii is a common cause of healthcare-associated infections (HAI) worldwide, mostly occurring in intensive care units (ICUs). Extended-spectrum beta lactamases (ESBL)-positive A. baumannii strains have emerged as highly resistant to most currently used antimicrobial agents, including carbapenems. The most common mechanism for carbapenem resistance in this species is ß-lactamase-mediated resistance. Carbapenem-hydrolyzing class D oxacillinases are widespread among multidrug-resistant (MDR) A. baumannii strains. The present study was conducted to determine the presence and distribution of blaOXA genes among multidrug-resistant A. baumannii isolated from ICU patients and genes encoding insertion sequence (IS-1) in these isolates. Additionally, the plasmid DNA profiles of these isolates were determined. A total of 120 clinical isolates of A. baumannii from various ICU clinical specimens of four main Jordanian hospitals were collected. Bacterial isolate identification was confirmed by biochemical testing and antibiotic sensitivity was then assessed. PCR amplification and automated sequencing were carried out to detect the presence of blaOXA-51, blaOXA-23, blaOXA-24, and blaOXA-58 genes, and ISAba1 insertion sequence. Out of the 120 A. baumannii isolates, 95% of the isolates were resistant to three or more classes of the antibiotics tested and were identified as MDR. The most frequent resistance of the isolates was against piperacillin (96.7%), cephalosporins (97.5%), and ß-lactam/ß-lactamase inhibitor combinations antibiotics (95.8%). There were 24 (20%) ESBL-producing isolates. A co-existence of blaOXA-51 gene and ISAba1 in all the 24 ESBL-producing isolates was determined. In addition, in the 24 ESBL-producing isolates, 21 (87.5%) carried blaOXA-51 and blaOXA-23 genes, 1 (4.2%) carried blaOXA-51 and blaOXA-24, but all were negative for the blaOXA-58 gene. Plasmid DNA profile A and profile B were the most common (29%) in ESBL-positive MDR A. baumannii isolates while plasmid DNA profile A was the most common in the ESBL-negative isolates. In conclusion, there was an increase in prevalence of MDR-A. baumannii in ICU wards in Jordanian hospitals, especially those having an ESBL phenotype. Thus, identification of ESBL genes is necessary for the surveillance of their transmission in hospitals.

17.
Forensic Sci Int ; 341: 111502, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36371979

RESUMEN

In forensic crime scene investigations, biological fluids such as blood are commonly found in soil. However, the analysis of blood-stained soil can be challenging due to the presence of inhibitors which limit the effective extraction and amplification of the deoxyribonucleic acid (DNA) required to produce a reportable DNA profile. There are some extraction methods that have been applied to blood-stained soil in forensic science, but these have produced sporadic results. This research has taken a number of different extraction methods from the fields of ancient DNA and environmental DNA and broken them down into the individual steps of pre-treatment, incubation, separation and purification. These steps were assessed independently then combined into various extraction methods to determine the best technique that can effectively and reliably profile human DNA from blood-stained soil. Testing involved assessment of three extraction buffers, (cetyltrimethylammonium bromide, guanidine thiocyanate, and proteinase K), four pre-treatment methods, (polyvinylpyrrolidone, ethylenediaminetetraacetic acid, hydrochloric acid, and sodium hydroxide), three separation steps, (centrifugation, phenol chloroform, and chloroform) and four purification steps, (size exclusion chromatography, bind elute columns, isopropanol precipitation and silica magnetic beads). The most effective procedure was found to be a polyvinylpyrrolidone pre-treatment with a proteinase K extraction buffer followed by magnetic silica bead purification with or without centrifugation. However, centrifugation separation was found to be equally effective after the pre-treatment step as after the incubation step. Our results shows that most of the current forensic procedures would benefit from the addition of a pre-treatment step prior to processing through the automated DNA profiling pipeline.


Asunto(s)
Manchas de Sangre , Suelo , Humanos , Reacción en Cadena de la Polimerasa/métodos , ADN/análisis , Cloroformo/análisis , Povidona , Endopeptidasa K , Dióxido de Silicio
18.
Forensic Sci Int Genet ; 60: 102738, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35691141

RESUMEN

The importance of DNA evidence for gaining investigative leads demands a fast workflow for forensic DNA profiling performed in large volumes. Therefore, we developed software solutions for automated DNA profile analysis, contamination check, major donor inference, DNA database (DDB) comparison and reporting of the conclusions. This represents the Fast DNA IDentification Line (FIDL) and this study describes its development, validation and implementation in criminal casework at the authors' institute. This first implementation regards single donor profiles and major contributors to mixtures. The validation included testing of the software components on their own and examination of the performance of different DDB search strategies. Furthermore, end-to-end testing was performed under three conditions: (1) testing of scenarios that can occur in DNA casework practice, (2) tests using three months of previous casework data, and (3) testing in a casework production environment in parallel to standard casework practices. The same DNA database candidates were retrieved by this automated line as by the manual workflow. The data flow was correct, results were reproducible and robust, results requiring manual analysis were correctly flagged, and reported results were as expected. Overall, we found FIDL valid for use in casework practice in our institute. The results from FIDL are automatically reported within three working days from receiving the trace sample. This includes the time needed for registration of the case, DNA extraction, quantification, polymerase chain reaction and capillary electrophoresis. FIDL itself takes less than two hours from intake of the raw CE data to reporting. Reported conclusions are one of five options: (1) candidate retrieved from DDB, (2) no candidate retrieved from DDB, (3) high evidential value with regards to reference within the case, (4) results require examination of expert, or (5) insufficient amount of DNA obtained to generate a DNA profile. In our current process, the automated report is sent within three working days and a complete report, with confirmation of the FIDL results, and signed by a reporting officer is sent at a later time. The signed report may include additional analyses regarding e.g. minor contributors. The automated report with first case results is quickly available to the police enabling them to act upon the DNA results prior to receiving the full DNA report. This line enables a uniform and efficient manner of handling large numbers of traces and cases and provides high value investigative leads in the early stages of the investigation.


Asunto(s)
Dermatoglifia del ADN , ADN , ADN/genética , Dermatoglifia del ADN/métodos , Electroforesis Capilar , Humanos , Reacción en Cadena de la Polimerasa , Programas Informáticos
19.
Forensic Sci Int Genet ; 52: 102462, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33465757

RESUMEN

We describe a method to assign weights to genotype combinations at the Amelogenin locus. It is a typical practise in forensic laboratories that once the weight exceeds a threshold (such as 99 %), then they can be considered to be resolved enough to interpret (for example to load onto a database). We found that unless an individual is a clear major (or minor) contributor, the genotype weights do not typically exceed 99 % for any genotype. LRs have not been traditionally assigned for the Amelogenin locus and are small compared to an LR assigned for a modern day STR multiplex where, for a more discriminatory locus, the per locus LR for a resolved contributor could be in the order of tens or hundreds. The method described uses per contributor template values for a previously interpreted profile. The discrimination power is restricted, with a maximum possible LR of 2 for a fully resolved genotype, due to the limited number of alleles and hence genotypes and assuming equal proportions of genders in the population. However, it has a good power to exclude when the component is well resolved and non-concordant with a POI.


Asunto(s)
Amelogenina/genética , Genética Forense , Funciones de Verosimilitud , Cromosomas Humanos X , Cromosomas Humanos Y , Dermatoglifia del ADN , Femenino , Genotipo , Humanos , Masculino , Repeticiones de Microsatélite , Reacción en Cadena de la Polimerasa
20.
J Law Biosci ; 8(1): lsab022, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34188945

RESUMEN

Universal forensic DNA databases are controversial privacy-wise given their omnibus scope of incorporating DNA profile data of the entire population into the system. Following the landmark decision of the European Court of Human Rights on the retention of DNA profiles in S. and Marper v. the United Kingdom, two differing opinions emerged on its application to universal databases: their acceptability and illegality. This paper makes use of the elements of the right to respect for private life (Article 8 ECHR), distilled from the Court's jurisprudence involving collection and retention of DNA profile data, in the form of tests-preliminary interference, legality, legitimate purpose, and proportionality-in assessing the feasibility of establishing population-wide DNA databases in Europe.

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