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1.
Todd Bille M.Sc. Jo‐Anne Bright M.Sc. John Buckleton Ph.D. 《Journal of forensic sciences》2013,58(2):474-485
Mixed DNA profiles are being encountered more frequently as laboratories analyze increasing amounts of touch evidence. If it is determined that an individual could be a possible contributor to the mixture, it is necessary to perform a statistical analysis to allow an assignment of weight to the evidence. Currently, the combined probability of inclusion (CPI) and the likelihood ratio (LR) are the most commonly used methods to perform the statistical analysis. A third method, random match probability (RMP), is available. This article compares the advantages and disadvantages of the CPI and LR methods to the RMP method. We demonstrate that although the LR method is still considered the most powerful of the binary methods, the RMP and LR methods make similar use of the observed data such as peak height, assumed number of contributors, and known contributors where the CPI calculation tends to waste information and be less informative. 相似文献
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The high number of murder, rape, and child abuse cases in South Africa has led to increased numbers of bite mark cases being heard in high courts. Objective analysis to match perpetrators to bite marks at crime scenes must be able to withstand vigorous cross-examination to be of value in conviction of perpetrators. An analysis technique is described in four stages, namely determination of the mark to be a human bite mark, pattern association analysis, metric analysis and comparison with the population data, and illustrated by a real case study. New and accepted techniques are combined to determine the likelihood ratio of guilt expressed as one of a range of conclusions described in the paper. Each stage of the analysis adds to the confirmation (or rejection) of concordance between the dental features present on the victim and the dentition of the suspect. The results illustrate identification to a high degree of certainty. 相似文献
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目的观察分析河南汉族人群中27个Y-STR基因座的突变情况。方法收集1 000对经常染色体STR检测确定父子关系的血样本,采用STRtyper-27Y系统扩增27个Y-STR基因座分型,统计各基因座发生突变次数和类型,计算突变率以及95%CI(可信区间)。结果 27个基因座中共有27 000次等位基因传递,共发现涉及24个基因座共92次突变,平均突变率(95%CI)为3.4×10-3(2.7~4.2×10-3),其中一步突变90次(97.8%),两步突变2次(2.2%);突变共涉及89对父子,其中86对仅1个基因座发生突变(96.6%),3对同时有2个基因座发生突变(3.4%)。等位基因增加突变与等位基因减少突变分别为43次和49次,两者比例为1∶1.14。结论河南汉族人群Y-STR基因座突变可涉及基因座较多,因此在数据库建设与日常检案中应注意防止错判。 相似文献
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At The Office of the Cuyahoga County Coroner (CCCO), Cleveland, Ohio, it is customary to perform an autopsy and conduct toxicological testing on decedents less than 19 years of age. This study provides a retrospective evaluation of drugs detected in a pediatric postmortem population between the years 1998 and 2002 (n = 730). Demographic information, cause and manner of death, and toxicological results were examined. Blacks comprised 54% of cases, males 59%, and 48% were less than one year of age or stillborn. Forty-two percent of deaths were ruled natural, 27% accident, 13% undetermined, 5% suicide, and 2% homicide. Of the 640 cases subjected to comprehensive testing, 38% of the cases were positive for at least one compound. Resuscitative/treatment drugs were detected most frequently (56% of positive results), followed by illicit drugs (26%), ethanol (11%), carbon monoxide (8%), and antihistamines (6%). Eighty-seven cases contained more than one drug. The deaths of 47 individuals were drug related (6%). In this population, it is recommended that illicit drugs and ethanol are targeted for testing, especially when limited specimens are available for analysis. 相似文献
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Bond JW 《Journal of forensic sciences》2007,52(1):128-136
DNA material is now collected routinely from crime scenes for a wide range of offences and the timely processing of the DNA is seen as key to its success in investigating and detecting crime. An analysis of DNA material recovered from the volume crime offences of residential burglary, commercial burglary, and theft of motor vehicle in Northamptonshire, U.K., in 2004 has enabled the DNA to be categorized into seven sources. Further analysis using a logistical regression has revealed a number of predictors, other than timeliness, that greatly influence whether the DNA material recovered from a crime scene enables the crime to be detected. The results indicate that a number of these predictors are of statistical significance and may be just as relevant in determining whether DNA successfully detects the crime as the timeliness of the processing of the DNA material. The most significant predictor was found to be investigating officer accreditation with location, quantity, and type of DNA material at the crime scene also being relevant. Accreditation of the Crime Scene Examiner recovering the DNA material was found not to be significant. Consideration is given to where further emphasis is needed by the U.K. police service to maximize the opportunities to detect volume crime with DNA. 相似文献
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POPULATION: African (n=52), Mixed Ancestry (n=5), Caucasian (n=4) SAN (n=1). 相似文献
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Karaman F 《Journal of forensic sciences》2006,51(3):630-635
Mesiodistal and buccolingual measurements, commonly used as a means of sex determination from teeth, can sometimes cause difficulties. The aim of this study is to test whether diagonal measurements can make it possible to take more accurate measurements. The results of diagonal measurements of dental casts taken from 30 males and 30 females have been evaluated by discriminant function statistics. Intra- and interobserver error tests did not indicate any statistically significant differences between the findings of two observers. Seven of the 14 measurements on the maxilla and 10 of the 14 measurements on the mandible have been found to be significantly greater in males. According to the results of the stepwise discriminant function statistics, the most contributory measurements to the function were upper first incisor mesiobuccal-distolingual (MBDL) and distobuccal-mesiolingual, lower second incisor MBDL, and lower canine MBDL. The highest reliability was obtained in MBDL measurements. It was realized that diagonal measurements of teeth, especially of canines, revealed clear dimorphic differences. Classification accuracy was found to be 83.3% for total sample, 78.3 for upper jaw, and 85.0% for the lower jaw. Accuracy rate was higher in the lower teeth. Commonly seen orthodontic anomalies, such as tooth rotations, crowding, attritions, deep dentin-enamel junction defects, and certain types of fillings, could make it difficult to correctly take width measurements or could cause other mistakes to occur. This explains the reason why this research has been considered to be of some use in diagonal measurements, which is an accurate method, particularly when employed for the front teeth. 相似文献
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A Practical Guide for the Formulation of Propositions in the Bayesian Approach to DNA Evidence Interpretation in an Adversarial Environment 下载免费PDF全文
Simone Gittelson Ph.D. Tim Kalafut Ph.D. Steven Myers M.S. Duncan Taylor Ph.D. Tacha Hicks Ph.D. Franco Taroni Ph.D. Ian W. Evett D.Sc. Jo‐Anne Bright Ph.D. John Buckleton D.Sc. 《Journal of forensic sciences》2016,61(1):186-195
The interpretation of complex DNA profiles is facilitated by a Bayesian approach. This approach requires the development of a pair of propositions: one aligned to the prosecution case and one to the defense case. This note explores the issue of proposition setting in an adversarial environment by a series of examples. A set of guidelines generalize how to formulate propositions when there is a single person of interest and when there are multiple individuals of interest. Additional explanations cover how to handle multiple defense propositions, relatives, and the transition from subsource level to activity level propositions. The propositions depend on case information and the allegations of each of the parties. The prosecution proposition is usually known. The authors suggest that a sensible proposition is selected for the defense that is consistent with their stance, if available, and consistent with a realistic defense if their position is not known. 相似文献
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Barbosa AB da Silva LA Azevedo DA Balbino VQ Mauricio-da-Silva L 《Journal of forensic sciences》2008,53(1):142-146
The sequences of the two hypervariable (HV) segments of the mitochondrial DNA (mtDNA) control region were determined in 167 randomly selected, unrelated individuals living in the state of Alagoas, north-eastern Brazil. One hundred and forty-five different haplotypes, associated with 139 variable positions, were determined. More than 95% of the mtDNA sequences could be allocated to specific mtDNA haplogroups according to the mutational motifs. Length heteroplasmy in the C-stretch HV1 and HV2 regions was observed in 22 and 11%, respectively, of the population sample. The genetic diversity was estimated to be 0.9975 and the probability of two random individuals presenting identical mtDNA haplotypes was 0.0084. The most frequent haplotype was shared by six individuals. All sequences showed high-quality values and phantom mutations were not detected. The diversity revealed in the mitochondrial control region indicates the importance of this locus for forensic casework and population studies within Alagoas, Brazil. 相似文献
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Exploring the Impacts of Ordinary Laboratory Alterations During Forensic DNA Processing on Peak Height Variation,Thresholds, and Probability of Dropout, 下载免费PDF全文
Kayleigh E. Rowan M.S. Genevieve A. Wellner M.S. Catherine M. Grgicak Ph.D. 《Journal of forensic sciences》2016,61(1):177-185
Impacts of validation design on DNA signal were explored, and the level of variation introduced by injection, capillary changes, amplification, and kit lot was surveyed by examining a set of replicate samples ranging in mass from 0.25 to 0.008 ng. The variations in peak height, heterozygous balance, dropout probabilities, and baseline noise were compared using common statistical techniques. Data indicate that amplification is the source of the majority of the variation observed in the peak heights, followed by capillary lots. The use of different amplification kit lots did not introduce variability into the peak heights, heterozygous balance, dropout, or baseline. Thus, if data from case samples run over a significant time period are not available during validation, the validation must be designed to, at a minimum, include the amplification of multiple samples of varying quantity, with known genotype, amplified and run over an extended period of time using multiple pipettes and capillaries. 相似文献
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Michael S. Adamowicz Ph.D. Renáe D. Labonte M.S. John E. Schienman Ph.D. 《Journal of forensic sciences》2015,60(4):1001-1011
Personal products, such as toothbrushes, have been used as both known reference and evidentiary samples for forensic DNA analysis. This study examined the viability of a broad selection of cosmetic applicators for use as targets for human DNA extraction and short tandem repeat (STR) analysis using standard polymerase chain reaction (PCR) conditions. Applicator types included eyeliner smudgers, pencils and crayons, eye shadow sponges, mascara wands, concealer wands, face makeup sponges, pads and brushes, lipsticks and balms, and lip gloss wands. The quantity and quality of DNA extracted from each type of applicator were examined by assessing the number of loci successfully amplified and the peak balance of the heterozygous alleles in each full STR profile. While degraded DNA, stochastic amplification, and PCR inhibition were observed for some items, full STR profiles were developed for 14 of 76 applicators. The face makeup sponge applicators yielded the highest proportional number of full STR profiles (4/7). 相似文献
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目的 调查分析17个Y-STR基因座等位基因突变的情况.方法 收集中国汉族人群867对父子共1 649份男性血样本.采用YfilerTM复合扩增试剂盒进行17个Y-STR基因座分型,共检测出14 739次等位基因传递,统计各基因座发生等位基因突变的频率.结果 在17个基因座中发现涉及13个基因座共41次突变,其中一步突变40次(97.6%),两步突变1次(2.4%);突变共涉及40对父子,其中39对仅1个基因座发生突变(97.5%),1对同时有2个基因座发生突变(2.5%);平均突变率为2.8×10-3(95%CI 2.0~3.8×10-3).等位基因突变时获得重复单位数19次,丢失重复单位数22次,两者比例接近.结论 中国汉族人群Y-STR基因座突变可涉及多数基因座,突变率在2.8×10-3左右,在数据库的建立与应用中应重视,注意采用相关方法进行甄别. 相似文献
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ABSTRACT: Before a Court of Law testifying in DNA‐evidence cases, scientists are often challenged with the idea that the more markers (loci) the better, i.e., why does the scientist not use 16 or more markers? This paper introduces a new perspective, decision analysis, to deal with the problem of the number of markers to type in a criminal context. The decision‐making process, which plays a key role in the routine work of a forensic scientist, consists of the rational choice, given personal objectives, between two or more possible outcomes when the consequences of the choice are uncertain. Simulated results support the hypothesis that analytical added value does not increase with the number of markers. 相似文献
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A Novel Method for the Photographic Recovery of Fingermark Impressions from Ammunition Cases Using Digital Imaging 下载免费PDF全文
Glenn Porter Ph.D. Robert Ebeyan B.Sc. Charles Crumlish B.A. Adrian Renshaw Ph.D. 《Journal of forensic sciences》2015,60(2):418-421
The photographic preservation of fingermark impression evidence found on ammunition cases remains problematic due to the cylindrical shape of the deposition substrate preventing complete capture of the impression in a single image. A novel method was developed for the photographic recovery of fingermarks from curved surfaces using digital imaging. The process involves the digital construction of a complete impression image made from several different images captured from multiple camera perspectives. Fingermark impressions deposited onto 9‐mm and 0.22‐caliber brass cartridge cases and a plastic 12‐gauge shotgun shell were tested using various image parameters, including digital stitching method, number of images per 360° rotation of shell, image cropping, and overlap. The results suggest that this method may be successfully used to recover fingermark impression evidence from the surfaces of ammunition cases or other similar cylindrical surfaces. 相似文献
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DNA分型实验室管理应重视的几个问题 总被引:1,自引:0,他引:1
1985年Gill等第一次报导将DNA指纹图用于个体讽别并获得成功后,DNA分型技术在个体识别和亲子鉴定中的应用潜力开始为法医界所注目【'].随着该项技术的日益完善,它极大地提高了生物学检材(血液,血痕,精斑,混合斑,毛发和指甲等)在法医物证学鉴定过程中的价值,并广泛应用于法医鉴定实践中.同时,法医界又面临着这样一个问题:如何对有关的DNA分型实验室进行管理监督,以保证其能更好地为司法实践服务.本文从DNA分型实验室人员设置和要求,DNA分型技术标准化以及与传统血型血清学的关系等方面并结合国外进展作如下探讨.ID… 相似文献
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Katelyn E. Mason Ph.D. Phillip H. Paul Ph.D. Fanny Chu M.S. Deon S. Anex Ph.D. Bradley R. Hart Ph.D. 《Journal of forensic sciences》2019,64(4):1152-1159
Shed human hair (lacking root nuclear DNA) frequently contributes important information to forensic investigations involving human identification. Detection of genetic variation observed in amino acid sequences of hair proteins provides a new suite of identity markers that augment microscopic hair analysis and mitochondrial DNA sequencing. In this study, a new method that completely dissolves single hairs using a combination of heat, ultrasonication, and surfactants was developed. Dissolved proteins were digested and genetically variant peptide (GVP) profiles were obtained for single hairs (25 mm) via high‐resolution nanoflow liquid chromatography‐based mass spectrometry and a novel exome‐driven bioinformatic approach. Overall, 6519 unique peptides were identified and a total of 57 GVPs were confirmed. Random match probabilities ranged between 2.6 × 10?2 and 6.0 × 10?9. The new bioinformatic strategy and ability to analyze GVPs in forensically relevant samples sizes demonstrate applicability of this approach to distinguish individuals in forensic contexts. 相似文献
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The Forensic Science Service (FSS) has devoted appreciable effort to developing the application of the principles of evidence interpretation. Much of the work has been reported in previous papers in this journal, in particular those that develop a model for Case Assessment and Interpretation (CAI). The principles of interpretation are restated and the implications for structure and content of statements are described. 相似文献