STR Genotyping from a Dry‐Cleaned Skirt in a Sexual Assault Case

In this sexual assault case, the standard preliminary semen examinations could not confirm physically or biochemically whether the accused's semen had stained the victim's skirt because the skirt had been dry‐cleaned for stain removal and had been worn for more than a year after the assault. Fortunately, however, a photograph taken just after the assault was found in the court records that showed white stains on the checkered skirt. The locations of the stains were estimated based on the checkered pattern of the fabric, and microscopic examination using Baecchi's staining revealed the presence of spermatozoa. Further analysis indicated the male DNA profile generated from the sperm cells was consistent with the suspect's DNA using three multiplex STR typing systems for a total of 21 autosomal and 17 Y chromosomal short tandem repeats (STRs). Ultimately, the result of the DNA profile played a very useful role as additional evidence.     

Forensic Application of SiFaSTRTM 23plex DNA ID System in Han Population of Eastern ChinaCSCD

Objective: To investigate the genetic polymorphism of 21 autosomal STR loci and DYS391 locus of SiFaSTRTM 23plex DNA ID system in Han population of eastern China and to evaluate its application value in forensic science. Methods: Typing test of 2 000 unrelated individuals was performed using SiFaSTRTM 23plex DNA ID system. The population genetic parameters of STR loci were statistically analysed. A total of 3 198 parentage confirmed cases were detected with that system and the mutation conditions were observed in 21 autosomal STR loci. Results: All the 21 autosomal STR loci showed no significant departure from Hardy-Weinberg equilibrium (P>0.05). The Ho ranged from 0.617 5 to 0.927 0. The DP ranged from 0.796 4 to 0.986 9, as well as the PIC distributed from 0.561 1 to 0.912 3. The CDP was 0.999 999 999 999 999. The CPEduo was 0.999 997 431 701 961, while CPEtrio was 0.999 999 999 654 865. Five alleles were detected in DYS391 locus, with the allele frequency from 0.004 0 to 0.729 0, and GD was 0.418 9. Except D13S317 and D10S1248, seventy-six mutation events were observed at the rest nineteen autosomal STR loci. Among them, seventy-five (98.68%) were one step mutation, and only one (1.32%) was three steps mutation. The mutation rate ranged from 0.246 5×10-3 to 2.711 4×10-3, and the averaged mutation rate was 0.892 1×10-3 (95% CI: 0.70×10-3-1.10×10-3). In 33 trio mutation cases, the proportion of the paternal mutation and the maternal mutation was 2.09 :1. Conclusion: The involved STRs are highly polymorphic in Eastern Han population with acceptable mutation rates by the SiFaSTRTM 23plex DNA ID system, which is suitable for paternity testing and individual identification. © 2018 by the Editorial Department of Journal of Forensic Medicine.     

Comparing persons found not criminally responsible on account of mental disorder for sexual offences versus nonsexual violent offences

Using data from the National Trajectory Project, we compared 50 individuals found Not Criminally Responsible on account of Mental Disorder (NCRMD) for sexual offences with 50 age- and gender-matched individuals found NCRMD for nonsexually violent offences. We also described the concurrent offenses, the symptoms at the time of the offense and the characteristics of the victims of offenders found NCRMD for sexual offences. Persons found NCRMD for sexual offences were less likely to be employed and were significantly younger at time of first psychiatric contact, but did not differ in other sociodemographic characteristics, other aspects of their psychiatric histories or in criminal history. Despite no differences in recidivism and no differences in behaviours between Review Board hearings when adjusting for unequal time at risk, persons found NCRMD for sexual offences had longer tenures under a Review Board mandate than persons found NCRMD for nonsexually violent offences. Given the many similarities between the two groups, this finding suggests that Review Boards may be unnecessarily conservative in how they manage sexual offenders.     

CO‐OFFENDING AND THE DEVELOPMENT OF THE DELINQUENT CAREER*

This article examines the role of co‐offending in the development of the delinquent career. Hypotheses derived from Reiss's (1986, 1988) taxonomic theory of co‐offending are tested, using police‐reported data on the delinquent careers and co‐offending of 55,336 Canadian offenders. Support is found for a taxonomic theory and for age‐related and functional theories of co‐offending. The taxonomy consists of two types of offenders—high activity (3 percent) and low activity (97 percent)—whose co‐offending patterns differ during the teenage years but not during childhood. For low‐activity offenders as teenagers, the proportion of co‐offenses decreases with criminal experience. The rate of co‐offending by high‐activity offenders as teenagers is lower at onset than for low‐activity offenders, and it varies little with criminal experience. For both offender types, the proportion of co‐offenses decreases with age, is slightly less in males, and varies with the type of offense. For both offender types, the proportion of co‐offenses in childhood offending is greater than in the teenage years and is unrelated to the offender's age or criminal experience.     

Fast Multiplexed Polymerase Chain Reaction for Conventional and Microfluidic Short Tandem Repeat Analysis

Abstract:  The time required for short tandem repeat (STR) amplification is determined by the temperature ramp rates of the thermal cycler, the components of the reaction mix, and the properties of the reaction vessel. Multiplex amplifications in microfluidic biochip-based and conventional tube-based thermal cyclers have been demonstrated in 17.3 and 19 min, respectively. Optimized 28-cycle amplification protocols generated alleles with signal strengths above calling thresholds, heterozygous peak height ratios of greater than 0.65, and incomplete nontemplate nucleotide addition and stutter of less than 15%. Full CODIS-compatible profiles were generated using the Profiler Plus ID, COfiler and Identifiler primer sets. PCR performance over a wide range of DNA template levels from 0.006 to 4 ng was characterized by separation and detection on a microfluidic electrophoresis system, Genebench-FX^™. The fast multiplex PCR approach has the potential to reduce process time and cost for STR analysis and enables development of a fully integrated microfluidic forensic DNA analysis system.     

A 26plex Autosomal STR Assay to Aid Human Identity Testing*†

Abstract: A short tandem repeat multiplex assay has been successfully developed with 25 autosomal loci plus the sex‐typing locus amelogenin for a total of 26 amplified products in a single reaction. Primers for the loci were designed so that all of the amplicons present were distributed from 65 base pairs (bp) to less than 400 bp within a five‐dye chemistry design with the fifth dye reserved for the sizing standard. A multiplex design strategy was developed to overcome challenges encountered in creating this assay. The limits of the multiplex were tested, resulting in the successful amplification of a wide range of genomic DNA sample concentrations from 2 ng to as low as 100 pg with 30 cycles of PCR. The 26plex has the potential to benefit the forensic community for reference sample testing and complex relationship evaluation.     

Use of Eucalyptus DNA profiling in a case of illegal logging

Eucalyptus is grown world-wide for paper pulp, solid wood, and other industries. Theft or illegal cutting of the trees causes hardship to owners of plantations and countries whose economies rely on the sale and export of eucalyptus products. Unfortunately, many of these crimes go unpunished due to lack of forensic evidence.Over 1200 short tandem repeat (STR) markers have been identified in the genomes of genus Eucalyptus and related species. However, their importance and utility in aiding forensic investigations of wood theft have not been explored. This study evaluated nine STRs for diversity and applied them to a case involving suspected wood theft.As expected, three dinucleotide STR markers showed greater variability but resulted in harder to interpret profiles. Four STR tetranucleotide markers evaluated in this study were found to contain additional repeat structures (dinucleotide or trinucleotide) that enhanced their variability but resulted in profiles with peaks at multiple stutter positions and heterozygote peak imbalance. The most promising STR markers were EGM37 and EMBRA 1374. Though less variable, they yielded robust and reproducible DNA profiles.All nine STR markers were applied to a case involving suspected wood theft. Samples were collected from seized wood and from remaining stumps in a plantation. No DNA match was found, thus eliminating the evidence samples as having originated from the forest. Dendrochronology analysis also resulted in an exclusion. This case study represents the first report using STR markers in any eucalyptus species to provide DNA evidence in a case of suspected wood theft.     

STR基因座与Amelogenin的峰面积比在DNA降解评估中的应用

目的研究DNA降解过程中STR基因座与性别基因座Amelogenin(AMEL)峰面积比(STR/AMEL)的变化规律,探讨STR/AMEL值在评估DNA降解程度中的应用。方法取人体髂腰肌组织抽提DNA,分析DNaseⅠ酶人工降解后STR/AMEL值(Penta E/AMEL、Penta D/AMEL、FGA/AMEL)的变化,并分析室外环境自然降解的髂腰肌组织中三者比值的变化。以降解时间为自变量(x),STR/AMEL值为因变量(y),进行回归曲线分析,建立两种条件下三组曲线方程。结果人工降解及自然降解条件下STR/AMEL值与降解时间均呈负相关,一元三次方程能够较好地模拟STR/AMEL值随降解时间的变化规律。人工降解条件下,R~2均大于0.99;自然降解条件下,R~2均大于0.86。结论 STR/AMEL值(Penta E/AMEL、Penta D/AMEL、FGA/AMEL)与DNA降解程度呈负相关,有望应用于DNA降解程度的评估。     

vWFⅢ基因座扩增片段长度多态性及其法医学应用

研究短串联重复vWⅢ基因应扩增片段长度多态性及其法医学意义。应用STR－PCR分型法对200名中国辽宁汉族无关个体的短串联重复VWFⅢ的多态性进行调查。共检出8个等位基因,频率分布在0．003～0．333,基因长度范围为154～182bP,个人识别能力为0．921,非父排除率为0．581。群体调查证实该基因座符合Hardy－Weinberg平衡,家系调查结果表明其遗传符合孟德尔方式。该基因座可作为人类群体遗传学的一个有价值的多态性标记,可用于法医学个人识别及亲子鉴定。     

Exploring the Social and Individual Differences Among Victims,Offenders, Victim-Offenders,and Total Abstainers

An emerging line of research has begun to reveal that victims of crime share many characteristics with offenders, leading to the conclusion that the victim-offender overlap is quite substantial. Though research suggests victims and offenders are both likely to display signs of low self-control and to share certain lifestyle factors, few studies have sought to systematically analyze the various factors that converge (or diverge) across different groups: victims, offenders, victim-offenders, and total abstainers. Using data obtained from the National Longitudinal Study of Adolescent to Adult Health (Add Health), we examined the risk factors associated with being classified into each of the four groups. Results revealed that victim-offenders—compared to others—tended to have the highest scores on risk factors for victimization and offending. Conversely, total abstainers tended to score the lowest on measures considered risk factors. Respondents classified as victim only and those classified as offender only were positioned somewhere between victim-offenders and total abstainers in terms of their level of exposure to risk factors. These findings may indicate that victim-offenders are a statistical group in need of greater attention, especially given the benefits that could extend to the broader population if successful outcomes through intervention were realized.