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1.
Int J Legal Med ; 138(5): 2057-2064, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38696127

RESUMEN

After in vitro fertilization with a single embryo, the parents learned about being pregnant with twins in the 10th week with various indications that an embryonic mix-up could have taken place. The affected couple thus expressed the urgent desire for a clarification of parenthood considering an abortion. However, the prenatal test results would not have been available until the 14/15th week of pregnancy. Legally, then, severe physical or mental distress of the pregnant woman must be claimed by physicians to justify an abortion after the twelfth week. However, a lack of genetic relatedness could lead to serious psychological distress for the parents, making a pregnancy termination possible even after the twelfth week, which is discussed in this case study alongside the interdisciplinary team's ethical, legal, and medical considerations.For the invasive relationship testing, cultivated chorionic villi samples (CVS) from both unborn and saliva samples from the putative parents were genetically analyzed using classical short tandem repeats (STR) analysis. The perfect match of both CVS profiles suggested the occurrence of an unusual late twin shaft, for which, fortunately, parenthood could be confirmed. To our knowledge, this is the first report on a prenatal investigation of a suspected embryo mix-up after assisted reproductive technology (ART), in which parenthood should be fixed. We want to draw attention to this unthinkable scenario, which may increase in the future with ART-induced rising multiple pregnancies.


Asunto(s)
Fertilización In Vitro , Humanos , Embarazo , Femenino , Adulto , Repeticiones de Microsatélite , Embarazo Gemelar , Muestra de la Vellosidad Coriónica , Masculino , Gemelos
2.
Forensic Sci Res ; 9(2): owae020, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38617445

RESUMEN

The goal of the following study is to clarify whether the skeletal remains over 70 years old from missing persons and their alleged relatives shared identical Y-STR loci. Nowadays, advances in ancient DNA extraction techniques and approaches of using multiple different Y-STRs have significantly increased the possibility of obtaining DNA profiles from highly degraded skeletal remains. Given the ages and conditions of the skeletal remains, ancient DNA extraction methods can be used to maximize the probability of DNA recovery. Considering that information about distant relatives is more relevant for long-term missing persons and alleged family members are male, Y-STR loci analysis is considered the most appropriate and informative approach for determining paternal lineage relationship. In this study, Y-STR genotypes obtained from these alleged relatives were identical to each other and to the alleles of missing persons' consensus profiles at more than 22 loci examined, whilst not being found in Y-STR population database from Y-Chromosome STR Haplotype Reference Database. Therefore, Missing Person No.7 and Missing Person No.18 have a patrilineal relationship with reference samples from Family1 and Family2, respectively. In addition, the fact that Y-STR haplotypes obtained from skeletal remains of missing persons and reference samples are not found in the Han Chinese people from East Asian demonstrates its rarity and further supports a paternal lineage relationship amongst them.

3.
Forensic Sci Int ; 353: 111856, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37863006

RESUMEN

This research evaluates the current DNA quantification (Quantifiler™ Trio, PowerQuant®, Investigator® Quantiplex® Pro and InnoQuant® HY Fast) and autosomal STRs amplification kits (GlobalFiler™, PowerPlex® Fusion 6 C, Investigator® 24Plex QS) using 62 degraded skeletal remains from armed conflicts (petrous bone, femur, tibia, and tooth) with several parameters (autosomal small, large, and male target, degradation index, probability of degradation, number of alleles above analytical threshold, number of alleles above stochastic threshold, RFU, peak height ratio, number of reportable loci). The best qPCR/autosomal STRs amplification tandem was determined by comparing quantification results by a DNA quantity estimation based on sample average RFU. InnoQuant® HY Fast was the most sensitive kit, and no significative differences were observed among amplification kits; however, Investigator® 24 Plex QS was found to be the most sensitive in our samples. That is why InnoQuant™ and Investigator® 24Plex QS were determined to be the best tandem.


Asunto(s)
Dermatoglifia del ADN , Diente , Masculino , Humanos , Dermatoglifia del ADN/métodos , Restos Mortales , Repeticiones de Microsatélite , ADN/análisis , Diente/química
4.
Methods Mol Biol ; 2685: 367-396, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37439994

RESUMEN

The RapidHIT™ ID System by Applied Biosystems allows the generation of a CODIS compatible STR profile in 90 min. The preloaded cartridges, fully automated workflow, and user-friendly computer interface allow for quick and simple single sample processing both in the laboratory and outside by non-laboratory personnel, like law enforcement officers. DNA processing utilizes a direct amplification workflow to generate an STR profile targeting the CODIS or ESS core loci. In conjunction with the RapidLINK™ Software, the system performs an initial analysis, flagging any profiles that do not meet single-source full profile parameters. Additionally, the RapidLINK™ allows for users to manage a multi-instrument/multi-location Rapid DNA system and view results in real-time. This gives users off-site the ability to track and even analyze results. The system allows for rapid reference sample analysis in locations like booking stations and national or border security agencies to obtain quick feedback of database hits for investigative leads while the subject is still in custody. RapidHIT™ ID DNA systems can also be set up at sites to aid in victim identification during mass disasters. The following chapter describes the process of generating a forensic DNA profile using the RapidHIT™ ID instrumentation from start to finish. Additionally, basic use and analysis using the RapidLINK™ and GeneMarker™ HID software is included.


Asunto(s)
Dermatoglifia del ADN , Repeticiones de Microsatélite , Dermatoglifia del ADN/métodos , Reacción en Cadena de la Polimerasa , Reproducibilidad de los Resultados , ADN/genética
5.
J Forensic Sci ; 68(4): 1133-1147, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37282776

RESUMEN

Touch DNA has become increasingly important evidence in todays' forensic casework. However, due to its invisible nature and typically minute amounts of DNA, the collection of biological material from touched objects remains a particular challenge that underscores the importance of the best collection methods for maximum recovery efficiency. So far, swabs moistened with water are often utilized in forensic crime scene investigations for touch DNA sampling, even though an aqueous solution provokes osmosis, endangering the cell's integrity. The aim of the research presented here was to systematically determine whether DNA recovery from touched glass items can be significantly increased by varying swabbing solutions and volumes compared with water-moistened swabs and dry swabbing. A second objective was to investigate the possible effects of storage of swab solutions prior to genetic analysis on DNA yield and profile quality when stored for 3 and 12 months, as is often the case with crime scene samples. Overall, the results indicate that adapting volumes of the sampling solutions had no significant effect on DNA yield, while the detergent-based solutions performed better than water and dry removal, with the SDS reagent yielding statistically significant results. Further, stored samples showed an increase in degradation indices for all solutions tested, but no deterioration in DNA content and profile quality, allowing for unrestricted processing of touch DNA samples stored for at least 12 months. One further finding was a strong intraindividual change in DNA amounts observed over the 23 deposition days which may be related to the donor's menstrual cycle.


Asunto(s)
Dermatoglifia del ADN , Tacto , Femenino , Humanos , Dermatoglifia del ADN/métodos , ADN/análisis , Indicadores y Reactivos , Manejo de Especímenes/métodos , Agua , Repeticiones de Microsatélite
6.
Int J Mol Sci ; 24(5)2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36902492

RESUMEN

Every week, 1-2 breeds of farm animals, including local cattle, disappear in the world. As the keepers of rare allelic variants, native breeds potentially expand the range of genetic solutions to possible problems of the future, which means that the study of the genetic structure of these breeds is an urgent task. Providing nomadic herders with valuable resources necessary for life, domestic yaks have also become an important object of study. In order to determine the population genetic characteristics, and clarify the phylogenetic relationships of modern representatives of 155 cattle populations from different regions of the world, we collected a large set of STR data (10,250 individuals), including unique native cattle, 12 yak populations from Russia, Mongolia and Kyrgyzstan, as well as zebu breeds. Estimation of main population genetic parameters, phylogenetic analysis, principal component analysis and Bayesian cluster analysis allowed us to refine genetic structure and provided insights in relationships of native populations, transboundary breeds and populations of domestic yak. Our results can find practical application in conservation programs of endangered breeds, as well as become the basis for future fundamental research.


Asunto(s)
Estructuras Genéticas , Animales , Bovinos , Filogenia , Teorema de Bayes , Federación de Rusia
7.
J Forensic Sci ; 68(3): 1049-1063, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36847295

RESUMEN

Two probabilistic genotyping (PG) programs, STRMix™ and TrueAllele™, were used to assess the strength of the same item of DNA evidence in a federal criminal case, with strikingly different results. For STRMix, the reported likelihood ratio in favor of the non-contributor hypothesis was 24; for TrueAllele it ranged from 1.2 million to 16.7 million, depending on the reference population. This case report seeks to explain why the two programs produced different results and to consider what the difference tells us about the reliability and trustworthiness of these programs. It uses a locus-by-locus breakdown to trace the differing results to subtle differences in modeling parameters and methods, analytic thresholds, and mixture ratios, as well as TrueAllele's use of an ad hoc procedure for assigning LRs at some loci. These findings illustrate the extent to which PG analysis rests on a lattice of contestable assumptions, highlighting the importance of rigorous validation of PG programs using known-source test samples that closely replicate the characteristics of evidentiary samples. The article also points out misleading aspects of the way STRMix and TrueAllele results are routinely presented in reports and testimony and calls for clarification of forensic reporting standards to address those problems.


Asunto(s)
Dermatoglifia del ADN , Programas Informáticos , Genotipo , Dermatoglifia del ADN/métodos , Funciones de Verosimilitud , Incertidumbre , Reproducibilidad de los Resultados , Repeticiones de Microsatélite , ADN/genética
8.
J Forensic Sci ; 68(1): 275-288, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36183153

RESUMEN

Since Y-STR typing only amplifies male Y chromosomal DNA, it can simplify the interpretation of some DNA mixtures that contain female DNA. However, if there are multiple male contributors, mixed Y-STR DNA profiles will often be obtained. Y-STR mixture analysis cases are particularly challenging though as, currently, there are no validated probabilistic genotyping (PG) software solutions commercially available to aid in their interpretation. One approach to fully deconvoluting these challenging mixtures into their individual donors is to conduct single-cell genotyping by isolating individual cells from a mixture prior to conducting DNA typing. In this work, a physical micromanipulation technique involving a tungsten needle and direct PCR with decreased reaction volume and increased cycle number was applied to equimolar 2- and 3-person buccal cell male DNA mixtures and a mock touch DNA case scenario involving the consecutive firing of a handgun by two males. A consensus DNA profiling approach was then utilized to obtain YFiler™ Plus Y-STR haplotypes. Buccal cells were used to optimize and test the direct single-cell subsampling approach, and 2-3 person male buccal cell mixtures were fully deconvoluted into their individual donor Y-STR haplotypes. Single-cell (or agglomerated cell clump) subsampling from the gun's trigger recovered single-source Y-STR profiles from both individuals who fired the gun, the owner, and the other unrelated male. Only the non-owner's DNA was found in the cells recovered from the handle. In summary, direct single-cell subsampling as described represents a potential simple way to analyze and interpret Y-STR mixtures.


Asunto(s)
Repeticiones de Microsatélite , Mucosa Bucal , Humanos , Masculino , Femenino , Dermatoglifia del ADN/métodos , Haplotipos , ADN/genética , Análisis de la Célula Individual , Cromosomas Humanos Y
9.
Int J Surg Pathol ; 31(5): 651-655, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35946122

RESUMEN

Epithelioid trophoblastic tumor (ETT) is a rare neoplasm derived from chorionic intermediate trophoblast cells, representing less than 2% of all gestational trophoblastic neoplasms. Classically, ETT presents as a uterine mass in women of reproductive age following a term pregnancy. The time from pregnancy to tumor development varies from months to several years. ETT most often arises in the endometrium, followed by the cervix. Extrauterine ETT are extremely infrequent, with few cases reported in the literature. We report a case of a 41-year-old woman, with history of three term pregnancies who presented with abdominal pain and elevated beta human chorionic gonadotropin (ß-hCG) level, ten years after her last pregnancy. Imaging reported a 3.5 cm adnexal mass, suspicious for ectopic pregnancy. Hysterectomy and mass resection revealed a 4.7 cm, tan-yellow, necrotic mass adjacent to the broad ligament. Histologic evaluation in conjunction with immunohistochemical stains revealed a tumor consistent with ETT. No connection to the endometrium was found grossly or microscopically. DNA fingerprinting analysis revealed the tumor to have two copies of paternal alleles, as seen in molar gestations. One of the primary differential diagnoses for ETT is squamous cell carcinoma due to similar morphologic features. In challenging cases, genetic analysis demonstrating paternally derived genes can establish the diagnosis. In this report, we discuss the challenges in the diagnosis of extrauterine ETT, due to its rarity and highly variable presentation, given that appropriate diagnosis is critical for correct patient management.


Asunto(s)
Enfermedad Trofoblástica Gestacional , Embarazo Ectópico , Neoplasias Trofoblásticas , Neoplasias Uterinas , Embarazo , Humanos , Femenino , Adulto , Neoplasias Uterinas/patología , Enfermedad Trofoblástica Gestacional/patología , Gonadotropina Coriónica Humana de Subunidad beta , Diagnóstico Diferencial , Neoplasias Trofoblásticas/diagnóstico , Células Epitelioides/patología
10.
Genes (Basel) ; 13(8)2022 08 11.
Artículo en Inglés | MEDLINE | ID: mdl-36011340

RESUMEN

Mixed human deoxyribonucleic acid (DNA) samples present one of the most challenging pieces of evidence that a forensic analyst can encounter. When multiple contributors, stochastic amplification, and allele drop-out further complicate the mixture profile, interpretation by hand becomes unreliable and statistical analysis problematic. Probabilistic genotyping software has provided a tool to address complex mixture interpretation and provide likelihood ratios for defined sets of propositions. The MaSTR™ software is a fully continuous probabilistic system that considers a wide range of STR profile data to provide likelihood ratios on DNA mixtures. Mixtures with two to five contributors and a range of component ratios and allele peak heights were created to test the validity of MaSTR™ with data similar to real casework. Over 280 different mixed DNA profiles were used to perform more than 2600 analyses using different sets of propositions and numbers of contributors. The results of the analyses demonstrated that MaSTR™ provided accurate and precise statistical data on DNA mixtures with up to five contributors, including minor contributors with stochastic amplification effects. Tests for both Type I and Type II errors were performed. The findings in this study support that MaSTR™ is a robust tool that meets the current standards for probabilistic genotyping.


Asunto(s)
Dermatoglifia del ADN , Repeticiones de Microsatélite , ADN/análisis , ADN/genética , Dermatoglifia del ADN/métodos , Genotipo , Humanos , Funciones de Verosimilitud , Repeticiones de Microsatélite/genética , Reacción en Cadena de la Polimerasa , Programas Informáticos
11.
Int J Legal Med ; 136(3): 687-693, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35195781

RESUMEN

DNA persistence and DNA transfer are important features in the assessment of a crime scene. The question how long DNA may persist at a certain location is similarly important as the one how the DNA has been transferred to this location. Depending on the source of the DNA as well as the conditions at the crime scene, the answer to this question is quite difficult. In this study, persistence of DNA from epithelial abrasions, blood cells, and saliva cells in indoor and outdoor scenarios has been investigated with regard to exposure time and exposure conditions including sunlight, temperature, and humidity in summer and winter scenarios. Overall, we generated 338 epithelial samples, 572 blood samples, and 572 saliva samples. A complete profile of the cell/DNA donor after exposure could be obtained in 47%, 65%, and 58% of epithelial abrasions, blood samples, and saliva samples, respectively. Regarding blood samples, there were no differences between supporting materials cloth and plastic; however, the percentage of complete profiles was higher for saliva samples on plastic and for epithelial samples on cloth. In indoor scenarios, complete profiles could be recovered from nearly all blood and saliva samples up to 9 months, whereas the amount of epithelial complete profiles already started to decline after 3 months. In outdoor scenarios, we observed a tipping point at an exposure time of 3 months. Blood and saliva samples collected after this period displayed complete profiles in less than 25% of samples. After 12 months, no outdoor sample showed a complete profile. The results of this study facilitate decisions on the relevance of recovered DNA from crime scenes.


Asunto(s)
Dermatoglifia del ADN , ADN , Crimen , Humanos , Plásticos , Saliva
12.
Forensic Sci Int ; 329: 111061, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34736049

RESUMEN

A forensic DNA database comprises of thousands of DNA profiles generated from suspects, convicts or even from common people from society. It is used for the cross-matching of DNA profiles obtained from evidence items collected from a crime scene. These databases are playing a core role in clearing the innocent and solving the dead-end unresolved crimes ultimately leading to crime reduction. In March, 2017, a nine years old minor girl was raped in district Khushab (Province Punjab). The medico-legal examiner indicated brutal sexual violence on the victim. Police apprehended a suspect who was excluded as the source of foreign male DNA from tested evidence items. Thus the case put up a question mark on the capabilities and efficiency of the police. An unknown male DNA profile obtained from evidence items was uploaded to PFSA DNA Database to maintain record. Later on, a suspect was arrested by Karachi (Province Sindh) police in another rape case, DNA profile of suspect was searched in the PFSA DNA Database. This generated DNA profile matched with the foreign DNA profile obtained from evidence items of minor victim, hence this atrocious crime was resolved. PFSA DNA Database provides support to criminal prosecution and also leads to identify potential suspects. It took years of effort to develop the rich PFSA DNA Database which subsequently proved to be fruitful in the exoneration of innocents and conviction of offenders in criminal cases.


Asunto(s)
Criminales , Violación , Delitos Sexuales , Niño , ADN , Femenino , Humanos , Masculino , Policia
13.
J Forensic Leg Med ; 82: 102223, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34343925

RESUMEN

Human skin hosts a variety of microbes that can be transferred to surfaces ("touch microbiome"). These microorganisms can be considered as forensic markers similarly to "touch DNA". With this pilot study, we wanted to evaluate the transferability and persistence of the "touch microbiome" on a surface after the deposition of a fingerprint and its exposure for 30 days at room temperature. Eleven volunteers were enrolled in the study. Skin microbiome samples were collected by swabbing the palm of their hands; additionally, donors were asked to touch a glass microscope slide to deposit their fingerprints, that were then swabbed. Both human and microbial DNA was isolated and quantified. Amelogenin locus and 16 human STRs were amplified, whereas the V4 region of 16 S rRNA gene was sequenced using Illumina MiSeq platform. STR profiles were successfully typed for 5 out of 22 "touch DNA" samples, while a microbiome profile was obtained for 20 out of 22 "touch microbiome" samples. Six skin core microbiome taxa were identified, as well as unique donor characterizing taxa. These unique taxa may have relevance for personal identification studies and may be useful to provide forensic intelligence information also when "touch DNA" fails. Additional future studies including greater datasets, additional time points and a greater number of surfaces may clarify the applicability of "touch microbiome" studies to real forensic contexts.


Asunto(s)
Bacterias/clasificación , Bacterias/genética , Dermatoglifia del ADN/métodos , Microbiota , ARN Ribosómico 16S/análisis , Piel/microbiología , Tacto , Adulto , Anciano , Amelogenina/genética , ADN/aislamiento & purificación , Conjuntos de Datos como Asunto , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Masculino , Repeticiones de Microsatélite , Persona de Mediana Edad , Proyectos Piloto , Análisis de Secuencia de ARN
14.
Int J Legal Med ; 135(4): 1385-1393, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33948711

RESUMEN

Over recent years, DNA profiling techniques have become highly sensitive. Even small amounts of DNA at crime scenes can be analysed leading to new defence strategies. At court, defence lawyers rarely question the existence of a DNA trace (source level) but challenge how the DNA was transferred to the scene (activity level). Nowadays, the most common defence strategy is to claim that somebody else had stolen the defendant's gloves and used them while breaking and entering. In this study we tested this statement. Using gloves made of different material (cloth, leather, rubber) and varying secondary transfer surfaces (wood, metal, glass), we simulated a few of the most likely transfer scenarios that occur during breaking and entering. While we detected the presence of DNA on the outside of 92 of the 98 gloves tested, we observed only one case of secondary transfer in a total of 81 transfer experiments. This data demonstrates that secondary transfer under conditions resembling realistic conditions is a very rare event.


Asunto(s)
Dermatoglifia del ADN , ADN/aislamiento & purificación , Lateralidad Funcional , Guantes Protectores , Humanos , Propiedades de Superficie , Textiles , Factores de Tiempo
15.
Int J Legal Med ; 135(5): 1685-1693, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33950286

RESUMEN

The MinION nanopore sequencing device (Oxford Nanopore Technologies, Oxford, UK) is the smallest commercially available sequencer and can be used outside of conventional laboratories. The use of the MinION for forensic applications, however, is hindered by the high error rate of nanopore sequencing. One approach to solving this problem is to identify forensic genetic markers that can consistently be typed correctly based on nanopore sequencing. In this pilot study, we explored the use of nanopore sequencing for single nucleotide polymorphism (SNP) and short tandem repeat (STR) profiling using Verogen's (San Diego, CA, USA) ForenSeq DNA Signature Prep Kit. Thirty single-contributor samples and DNA standard material 2800 M were genotyped using the Illumina (San Diego, CA, USA) MiSeq FGx and MinION (with R9.4.1 flow cells) devices. With an optimized cutoff for allelic imbalance, all 94 identity-informative SNP loci could be genotyped reliably using the MinION device, with an overall accuracy of 99.958% (1 error among 2926 genotypes). STR typing was notably error prone, and its accuracy was locus dependent. We developed a custom-made bioinformatics workflow, and finally selected 13 autosomal STRs, 14 Y-STRs, and 4 X-STRs showing high consistency between nanopore and Illumina sequencing among the tested samples. These SNP and STR loci could be candidates for panel design for forensic analysis based on nanopore sequencing.


Asunto(s)
Técnicas de Genotipaje , Repeticiones de Microsatélite , Secuenciación de Nanoporos/métodos , Polimorfismo de Nucleótido Simple , Análisis de Secuencia de ADN/métodos , Marcadores Genéticos , Humanos , Proyectos Piloto
16.
Prenat Diagn ; 41(9): 1171-1178, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33434320

RESUMEN

OBJECTIVE: Enrichment of circulating trophoblasts (CTs) from maternal blood at week 11-13 of gestation, using laminar microscale vortices, and evaluation of the performance of the VTX-1 Liquid Biopsy System in terms of CT recovery and purity. METHOD: Eight mililiter of blood was collected from 15 pregnant women and processed with the VTX-1 Liquid Biopsy System. Y-chromosome specific quantitative PCR was performed to estimate the number of enriched male CTs. To evaluate the VTX-1 performance, the target cell recovery was characterized by spiking experiments with a trophoblast cell line. Furthermore, the total quantity of DNA after enrichment was used to calculate the number of retained maternal cells. RESULTS: Successful recovery of male CTs was established in 7 out of 10 first trimester samples from pregnant women carrying a male fetus. The number of CTs, recovered from 8 ml of blood, was estimated between two and six. Spiking experiments resulted in a CT recovery of ±35 % with ±1524 retained maternal blood cells. CONCLUSION: CTs can be enriched from maternal blood with high purity, using laminar microscale vortices, starting from 8 ml of blood.


Asunto(s)
Trofoblastos/metabolismo , Adulto , Recuento de Células Sanguíneas/métodos , Recuento de Células Sanguíneas/estadística & datos numéricos , Femenino , Feto/metabolismo , Edad Gestacional , Humanos , Reacción en Cadena de la Polimerasa/métodos , Embarazo , Diagnóstico Prenatal/métodos , Trofoblastos/fisiología
17.
Forensic Sci Int Genet ; 51: 102410, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33373910

RESUMEN

OSIRIS is a mathematically-based software tool for Short Tandem Repeat (STR) and DNA fragment analysis (https://www.ncbi.nlm.nih.gov/osiris/). As part of its routine sample analyses, OSIRIS computes unique quality metrics that can be used for sample quality assessment. A common artifact of STR analysis is cross-channel pull-up or pull-down (negative pull-up). This occurs because of the spectral overlap between the dyes used with the marker set, and the failure of the color deconvolution matrix to isolate the colors in the dye set adequately. This paper describes a mathematical method for analyzing and quantifying the pull-up patterns across sample channels and effectively identifying and correcting the pull-up artifacts, as implemented in OSIRIS. Unlike approaches to pull-up that require a training set composed of previous samples, the algorithm described here uses a mathematical model of the underlying causes of pull-up. It is based solely on the information intrinsic to the sample it is analyzing and therefore incorporates the effects of the ambient conditions and the specific procedures used in creating the sample. These conditions are the physical determinants of the level of pull-up in the sample and are not likely to be represented in a training set consisting of past samples.


Asunto(s)
Artefactos , Dermatoglifia del ADN , Repeticiones de Microsatélite , Modelos Teóricos , Genética Forense , Humanos , Programas Informáticos
18.
Forensic Sci Int Genet ; 49: 102373, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32871489

RESUMEN

Short tandem repeat (STR) analysis is prone to failure as DNA is frequently damaged by various environmental factors; hence, increasing the number of starting templates may constitute a feasible approach to improve STR profiling success. Whole genome amplification (WGA) is often applied to bolster starting template quantity. Moreover, WGA can reportedly be used on degraded DNA samples in forensics. Therefore, we utilized a PCR-based WGA method, termed "modified improved primer extension preamplification" (mIPEP), prior to STR analysis of degraded DNA, as this method is less affected by DNA quantity and quality than most others. Saliva from four volunteers was dried on glass fiber filter papers (paper) and glass slides (glass) and irradiated with UVA light (365 nm). The mIPEP method was initiated using 5, 0.5, and 0.05 ng of DNA following DNA extraction. The DNA degradation index (DI) was calculated based on the ratio of 129 to 41 bp DNA fragments; lower numbers indicate higher degradation. Following mIPEP, STR analysis was performed using the AmpFlSTR Identifiler PCR amplification kit. The number of detectable STR loci, with and without mIPEP, decreased according to reduced DI in a different manner for the various DNA concentrations extracted from paper and glass. Specifically, for the 5 ng DNA sample on paper, at a DI < 0.2, the number of detectable STR loci was greater with mIPEP than without it, owing to fewer locus drop-outs. Similarly, the 0.05 ng DNA sample deposited on paper, at DI ≥ 0.7, exhibited higher numbers of detectable STR loci when prepared using mIPEP owing to fewer allele drop-outs. Moreover, among samples deposited on glass, the 0.05 ng DNA sample at DI ≥ 0.4 afforded a larger number of detectable STR loci when prepared using mIPEP than those without mIPEP, owing to fewer locus drop-outs. These findings suggest that performing mIPEP in accordance with sample DNA condition (e.g., quantity and quality) may lead to increased success of STR analysis. Notably, the conditions identified as most responsive to mIPEP were consistent across both UVA-irradiated and environmentally-damaged sample states. Taken together, our results suggest that applying mIPEP would be beneficial to obtain improved STR profiles under conditions involving severely degraded samples with large quantities of DNA, or with small quantities of DNA albeit with slight degradation.


Asunto(s)
Degradación Necrótica del ADN , Dermatoglifia del ADN/métodos , Genoma Humano , Repeticiones de Microsatélite , Reacción en Cadena de la Polimerasa , Alelos , Humanos , Saliva/química
19.
Ecol Evol ; 10(15): 8368-8378, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32788986

RESUMEN

Cat predation upon bat species has been reported to have significant effects on bat populations in both rural and urban areas. The majority of research in this area has focussed on observational data from bat rehabilitators documenting injuries, and cat owners, when domestic cats present prey. However, this has the potential to underestimate the number of bats killed or injured by cats. Here, we use forensic DNA analysis techniques to analyze swabs taken from injured bats in the United Kingdom, mainly including Pipistrellus pipistrellus (40 out of 72 specimens). Using quantitative PCR, cat DNA was found in two-thirds of samples submitted by bat rehabilitators. Of these samples, short tandem repeat analysis produced partial DNA profiles for approximately one-third of samples, which could be used to link predation events to individual cats. The use of genetic analysis can complement observational data and potentially provide additional information to give a more accurate estimation of cat predation.

20.
Forensic Sci Int Genet ; 48: 102331, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32623352

RESUMEN

High throughput sequencing of multiplexed PCR amplicons with Short Tandem Repeats (STRs) requires software solutions that sort the information and allow a comprehensive overview of the results without overwhelming the data analyst with details. Here, we present an updated version (2.0) of the STR analysis tool STRinNGS. It is freely available as a Docker image or zip file ready for downloading. STRinNGS predicts genotypes using criteria for read depth, noise, flanking region lengths, mismatches in the flanking regions, locus balance, and heterozygote balance. Warning flags highlight suspicious genotypes as well as suspicious sequences that are not identified as either noise or alleles in the result table used for the manual analysis. STRinNGS analyses both the STR and the flanking regions, and names the alleles according to the STRidER guidelines as well as an in-house nomenclature that also include variants in the flanking regions. Furthermore, STRinNGS generates files with analysed data in a format that may be uploaded directly to the STRidER database. We re-analysed 627 sample files from eight different MiSeq FGx runs with STRinNGS v2.0. The samples were previously typed with the ForenSeq™ Signature Prep Kit and analysed with STRinNGS v1.0 and the Universal Analysis Software. Apart from three poorly performing loci with large heterozygote imbalances (Penta E and D22S1045) or frequent single nucleotide errors (DYS461), only 58 genotype calls (0.2 %) had to be manually corrected and only 14 genotype calls were discordant with the previous analyses. The discordant calls were primarily caused by manual oversights and in every case, the STRinNGS v2.0 analysis was correct.


Asunto(s)
Dermatoglifia del ADN , Secuenciación de Nucleótidos de Alto Rendimiento , Repeticiones de Microsatélite , Diseño de Software , Alelos , Genotipo , Humanos , Análisis de Secuencia de ADN , Programas Informáticos
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