STRtyper-10F/G联合CODIS系统鉴定突变三联体和二联体

目的 评估STRtyper-10F/G、CODIS系统联合应用在突变三联体和二联体亲子鉴定中的鉴定能力.方法 104例亲子鉴定样本,采用CODIS检测,其中3例三联体发现突变的案例以及101例二联体中73例认定和28例排除案例,分别再使用STRtyper-10F/G检测;统计认定和排除情况、比较单独使用和联合使用在排除关系案例中的表现和法医学参数(H、DP、PE、PIC、TPI).结果 3例存在突变基因的三联体案例加做STRtyper-10F/G未发现更多的矛盾基因座,PI值均大于10 000,可作出认定结论;73例二联体认定案例中13例PI不足10 000,加做STRtyper-10F/G系统后PI＞10 000,可确认认定;28例排除案例最高排除率CODIS为50.00％、STRtyper-10F/G为64.29％;两个体系均具有较高的杂合度(H≥0.7)和信息量(PIC ＞0.7),联合应用CEP为0.999 999 999 505 3.结论 STRtyper-10F/G和CODIS系统联合应用可满足突变三联体和二联体亲子鉴定的需要.     

Developmental validation of the AmpFℓSTR® Identifiler® Plus PCR Amplification Kit: an established multiplex assay with improved performance

Abstract: Analysis of length polymorphism at short tandem repeat (STR) loci utilizing multiplex polymerase chain reaction (PCR) remains the primary method for genotyping forensic samples. The AmpF?STR^® Identifiler^® Plus PCR Amplification Kit is an improved version of the AmpF?STR^® Identifiler^® PCR Amplification Kit and amplifies the core CODIS loci: D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, CSF1PO, FGA, TH01, TPOX, and vWA. Additional loci amplified in the multiplex reaction are the sex‐determinant, amelogenin, and two internationally accepted loci, D2S1338 and D19S433. While the primer sequences and dye configurations were unchanged, the AmpF?STR^® Identifiler^® Plus PCR Amplification Kit features an enhanced buffer formulation and an optimized PCR cycling protocol that increases sensitivity, provides better tolerance to PCR inhibitors, and improves performance on mixture samples. The AmpF?STR^® Identifiler^® Plus PCR Amplification Kit has been validated according to the FBI/National Standards and Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines. The validation results support the use of the AmpF?STR^® Identifiler^® Plus PCR Amplification Kit for human identity and parentage testing.     

Intimidation and Street Gangs: Understanding the Response of Victims and Bystanders to Perceived Gang Violence

While research routinely examines the influence of gang membership on the quantity of violent crime involvement, less is known about the influence of gang violence on the situational characteristics of violent victimization. Felson’s discussion of street gangs highlights the possible functional role gang membership plays in the commission of violent crime; what he terms “the street gang strategy.” This study examines the functionality of gang membership during violent crimes by investigating the influence of perceived gang membership on the likelihood of victim resistance, bystander intervention, and police reporting using data from the National Crime Victimization Survey. Findings offer little support for the idea that gang members intimidate victims and bystanders to the extent that their behavior during and after violence differs systematically from responses resulting from non‐gang violence. Results are discussed in terms of their policy relevance and implications for future research.     

Extended PCR conditions to reduce drop-out frequencies in low template STR typing including unequal mixtures

Forensic laboratories employ various approaches to obtain short tandem repeat (STR) profiles from minimal traces (<100 pg DNA input). Most approaches aim to sensitize DNA profiling by increasing the amplification level by a higher cycle number or enlarging the amount of PCR products analyzed during capillary electrophoresis. These methods have limitations when unequal mixtures are genotyped, since the major component will be over-amplified or over-loaded. This study explores an alternative strategy for improved detection of the minor components in low template (LT) DNA typing that may be better suited for the detection of the minor component in mixtures. The strategy increases the PCR amplification efficiency by extending the primer annealing time several folds. When the AmpF?STR^® Identifiler^® amplification parameters are changed to an annealing time of 20 min during all 28 cycles, the drop-out frequency is reduced for both pristine DNA and single or multiple donor mock case work samples. In addition, increased peak heights and slightly more drop-ins are observed while the heterozygous peak balance remains similar as with the conventional Identifiler protocol. By this extended protocol, full DNA profiles were obtained from only 12 sperm heads (which corresponds to 36 pg of DNA) that were collected by laser micro dissection. Notwithstanding the improved detection, allele drop-outs do persist, albeit in lower frequencies. Thus a LT interpretation strategy such as deducing consensus profiles from multiple independent amplifications is appropriate. The use of extended PCR conditions represents a general approach to improve detection of unequal mixtures as shown using four commercially available kits (AmpF?STR^® Identifiler, SEfiler Plus, NGM and Yfiler). The extended PCR protocol seems to amplify more of the molecules in LT samples during PCR, which results in a lower drop-out frequency.     

AGCU免提取STR荧光检测试剂盒的验证

目的考察AGCU免提取STR荧光检测试剂盒．对保存在滤纸片或FTA卡上血液样本的直接扩增检测情况。方法使用人GCU免提取STR荧光检测试剂盒,对未经提取的滤纸片血液样本、FTA卡血液样本675份进行直接扩增和18个基因座的DNA分型,并对结果的可靠性进行研究。结果18个基因座检测结果与PP16和ID试剂盒分型结果一致,2000年数据库样本成功率92．3％,2001年数据库样本成功率92．6％,2004以后年数据样本及案件样本、亲子鉴定样本成功率在99％以上。结论AGCU试剂盒可以成功地对滤纸片、FTA卡样本的18个STR基因座进行直接扩增检测,检验结果稳定,分型准确。     

X—STR基因座的法医学应用研究进展

对X染色体的结构特征、遗传特征及其短串联重复序列（STR）基因座在法医学领域的研究历史、现状进行了综述。并分析了X染色体STR基因座在混合斑鉴定和复杂亲子关系鉴定中的应用,以及在法医学领域应用中应注意的问题．如单倍型和连锁不平衡现象等。     

Isolation and Individualization of Conceptus and Maternal Tissues from Abortions and Placentas for Parentage Testing in Cases of Rape and Abandoned Newborns*

Abstract: Abortion specimens are often submitted to forensic laboratories as the only piece of physical evidence in rape and incest cases. The recovery of conceptus tissues from this evidence permits the use of paternity testing to evaluate suspects. In cases of abandoned newborns, the recovery of maternal tissue from the placenta allows for the direct comparison of genetic profiles between the suspected mother and the biological mother. We report on the identification and isolation of conceptus tissues from embryonic‐ and fetal‐period abortions, and maternal tissues from delivered placentas, by gross and low‐magnification examination with manual dissection. Hundreds of single‐source samples have been successfully recovered by this method and short tandem repeat typed using standard forensic procedures. We additionally describe extraembryonic tissues that can be recovered and typed in the absence of the embryo proper. We conclude that an expertise and protocols can be developed by forensic laboratories for the routine analysis of this evidence.     

Full Sibling Identification by IBS Scoring Method and Establishment of the Query Table of Its Critical ValueCSCD

Objective: To establish a query table of IBS critical value and identification power for the detection systems with different numbers of STR loci under different false judgment standards. Methods: Samples of 267 pairs of full siblings and 360 pairs of unrelated individuals were collected and 19 autosomal STR loci were genotyped by Goldeneye™ 20A system. The full siblings were determined using IBS scoring method according to the 'Regulation for biological full sibling testing'. The critical values and identification power for the detection systems with different numbers of STR loci under different false judgment standards were calculated by theoretical methods. Results: According to the formal IBS scoring criteria, the identification power of full siblings and unrelated individuals was 0.764 0 and the rate of false judgment was 0. The results of theoretical calculation were consistent with that of sample observation. The query table of IBS critical value for identification of full sibling detection systems with different numbers of STR loci was successfully established. Conclusion: The IBS scoring method defined by the regulation has high detection efficiency and low false judgment rate, which provides a relatively conservative result. The query table of IBS critical value for identification of full sibling detection systems with different numbers of STR loci provides an important reference data for the result judgment of full sibling testing and owns a considerable practical value. © 2017 by the Editorial Department of Journal of Forensic Medicine.     

Don’t stop believing: the relative impact of internal alibi details on judgments of veracity

The relative impact of five alibi components on the assessment of alibi veracity was investigated using a policy-capturing methodology. Participants (N?=?115) were instructed to assume the role of a homicide investigator and evaluate 32 alibis that varied on five dichotomous variables: Salaciousness; Legality; Change in Details; Superfluous Details; and Specific Details. Participants evaluated the believability of each alibi, and the likelihood of the alibi provider’s guilt. Results indicated that participants tended to disbelieve suspects when illegal or salacious behaviours were mentioned within the alibi. Few decision policies contained Change in Details, Superfluous Details, or Specific Details. The potential implications for alibi assessments during police investigations are discussed.     

基于下一代测序的全解析度STR分型研究进展与展望

下一代测序技术具有高通量、高速度、集成化、低成本等显著优势,近年来已在科研和临床诊断领域得到广泛应用,在法医遗传学领域亦具有重要应用前景。当前主流的STR分型方法仅关注序列的长度多态性,然而由于核心重复结构存在差异或扩增区段内存在SNP,序列长度相等的等位基因可能是具有遗传稳定性的完全不同的等位基因,此类STR序列多态性是个体识别或亲缘关系分析的宝贵资源。基于下一代测序的STR分型在现有数据输出方式基础上,允许进一步关注STR的序列多态性,对STR基因座进行全解析度分型,显著提升STR基因座的个体识别能力。本文以法医STR遗传标记和下一代测序技术为关注焦点,系统综述基于下一代测序的全解析度STR分型领域国际最新研究进展,深入探讨该技术在法医DNA实验室的实际应用潜力和可能面临的挑战,希冀对相关研究和实践提供参考。