常染色体STR遗传标记在同胞鉴定中的应用

目的 探讨常染色体STR遗传标记用于鉴定两个体同胞关系的可行性。方法 用Power Plex~(TM)16体系15个STR基因座检测150对同胞个体和150对无关个体,ITO法计算同胞关系指数(PI_(FS))与同胞关系概率(W_(FS)),并比较两组W_(FS)值及两个体间等位基因匹配情况的差异,对前者进行组间差异的x~2检验。结果 100对(66.67％)同胞个体的W_(FS)大于0.9995;无关个体W_(FS)均小于0.8,其中100对(66.67％)W_(FS)小于0.27。同胞个体两个体间等位基因全相同的基因座个数为1～10个不等,平均5.49个,无关个体0～5个不等,平均1.33个;等位基因全不同的基因座个数,同胞个体0～6个不等,平均1.66个,无关个体2～11个不等,平均6.57个;等位基因半相同的基因座个数,同胞个体3～13个不等,平均7.85个,而无关个体1～13个不等,平均7.11个。经x~2检验,同胞个体和无关个体间全相同和全不同的基因座数差异均有极显著意义(P<0.001),半相同的基因座数差异无显著意义(P>0.05)。结论 PowerPlex~(TM)16体系可用于鉴定同胞关系。当两个体全不同基因座个数大于或等于6个,或全相同基因座数为0时,提示为无关个体;当两个体全不同基因座个数小于或等于1个,或全相同基因座数大于或等于6个时,提示为同胞。     

性染色体及线粒体DNA遗传标记的法医学应用

对性染色体及线粒体DNA的结构特征、遗传特征等相关基础知识及其遗传标记在法医学领域应用的研究进展等进行了综述,分析了上述各类遗传标记在法医学领域应用的利弊,以促进非常染色体DNA遗传标记在法医学实践中的应用。     

法医器官组织特异性circRNAs的筛选及确证

目的 筛选并确证器官组织特异性circRNAs分子标记物,应用于法医器官组织溯源.方法 从TSCD数据库及文献中,筛选出器官组织特异性circRNAs,设计并验证引物.收集心脏、大脑、肝脏、皮肤、骨骼肌、肺脏等人体组织样本,经总RNA提取、RT-qPCR、琼脂糖凝胶电泳等步骤对候选circRNAs进行组织表达水平分析,...     

Application of plant DNA markers in forensic botany: genetic comparison of Quercus evidence leaves to crime scene trees using microsatellites

As highly polymorphic DNA markers become increasingly available for a wide range of plant and animal species, there will be increasing opportunities for applications to forensic investigations. To date, however, relatively few studies have reported using DNA profiles of non-human species to place suspects at or near crime scenes. Here we describe an investigation of a double homicide of a female and her near-term fetus. Leaf material taken from a suspect's vehicle was identified to be that of sand live oak, Quercus geminata, the same tree species that occurred near a shallow grave where the victims were found. Quercus-specific DNA microsatellites were used to genotype both dried and fresh material from trees located near the burial site and from the material taken from the suspect's car. Samples from the local population of Q. geminata were also collected and genotyped in order to demonstrate that genetic variation at four microsatellite loci was sufficient to assign leaves to an individual tree with high statistical certainty. The cumulative average probability of identity for these four loci was 2.06x10(-6). DNA was successfully obtained from the dried leaf material although PCR amplification was more difficult than amplification of DNA from fresh leaves. The DNA profiles of the dried leaves from the suspect's car did not match those of the trees near the crime scene. Although this investigation did not provide evidence that could be used against the suspect, it does demonstrate the potential for plant microsatellite markers providing physical evidence that links plant materials to live plants at or near crime scenes.     

Anionic markers for the forensic identification of Chemical Ignition Molotov Cocktail composition

An improved version of the famous Molotov cocktail is the Chemical Ignition Molotov Cocktail (CIMC). This incendiary device contains chemical reagents that enable its self-ignition. The analysis of anions from CIMC residues by capillary electrophoresis (CE) allows the identification of the reagents used to produce the device, and provides forensic analysts with valuable information. Although, sulfate, chlorate, chloride, and perchlorate anions have been recently proposed in the literature as target anions to determine the CIMC composition, the identification of some of them could be controversial due to their presence in the environment. Therefore, the purpose of this study was to identify highly reliable anions capable of indicating the components used to prepare these self-initiated devices. The relationship among the detected anions in CIMC residues and the reagents employed in their elaboration is discussed. Some anions have been proposed as anionic markers of CIMC as incendiary devices. Additionally, the viability of different CIMC compositions was studied.     

骨折法医鉴定中多层螺旋CT（MSCT）重建技术的应用分析

目的探讨MSCT及后处理功能在法医鉴定中的应用方法。方法对366例法医鉴定者行MSCT薄层扫描并表面遮盖成像(SSD),透明化X线模拟投影(see-through)和多平面重建(MPR)处理。分析技术参数和应用方法。结果采集层厚1~3mm,重建间隔0.5~1mm。SSD重建366例,其中细小骨折显示欠佳,4例眼眶重建出现“假孔”。21例关节分解后关节面显示清晰。透明化X线模拟投影重建18例,准确鉴别新鲜与陈旧骨折。MPR重建366例,显示骨折326例。结论选择适宜的后处理技术并联合应用可更好的显示骨折,为法医鉴定提供高质量图像。     

A method to enable forensic genetic genealogy investigations from DNA mixtures

The presence of more than one DNA contributor in an evidentiary sample may preclude attempts to use forensic genetic genealogy to develop an investigative lead. To address this issue, we developed a workflow for deconvolution of SNP mixtures into single source profiles that are suitable for matching against a genealogical database. Using the method, two-contributor DNA mixtures assayed using a commercial SNP typing kit can produce informative match results for both major and minor contributors.     

30个 InDels在中国三个民族的遗传学调查及法医学应用

目的调查Qiagen Investigator@ DIPplex试剂盒30个InDels多态性位点在中国汉族、藏族、维吾尔族人群中的群体遗传学数据,评估其法医学应用价值。方法采集汉、藏、维吾尔族各90名无关个体静脉血,提取DNA。使用3130xL毛细管电泳对该270份样品进行分型,通过统计计算相关的群体遗传学参数。结果实验得到270份样品的分型及基因型频率,30个InDels未明显偏离Hardy-Weinberg平衡及连锁平衡,在汉族、藏族、维吾尔族三个人群中的随机匹配概率分别为1.42×10（-11）、7.19×10（-12）、4.74×10（-13）,累积非父排除率（CPE）均大于0．9951。结论该组插入缺失位点在中国的汉族、藏族、维吾尔族人群中具有较高的多态性,能达到较高的个体识别能力,可以作为现有STR检验体系的补充。     

MSCT及图像后处理在鼻骨骨折法医鉴定中的应用

目的探讨多层螺旋CT(MSCT)及图像后处理在鼻骨骨折法医学鉴定中的应用价值。方法采用MSCT对134例被鉴定人进行薄层扫描并行多平面重建(MPR)和表面遮盖成像(SSD)。比较MSCT与常规X线诊断结果。结果线型骨折55(41.04%)例,粉碎型骨折46例(34.33%),凹陷型骨折27例(20.15%),未见骨折6例(4.48%)。X线平片及CR片漏、误诊48例(35.82%)。MSCT正确诊断133例(99.25%)。两者诊断结果存在显著差异(χ2=45.0816,P<0.001)。结论MSCT及后处理图像应作为鼻骨骨折法医鉴定的主要依据。     

Validation of the barcoding gene COI for use in forensic genetic species identification

The application of forensics to wildlife crime investigation routinely involves genetic species identification based on DNA sequence similarity. This work can be hindered by a lack of authenticated reference DNA sequence data resulting in weak matches between evidence and reference samples. The introduction of DNA barcoding has highlighted the expanding use of the mtDNA gene, cytochrome c oxidase I (COI), as a genetic marker for species identification. Here, we assess the COI gene for use in forensic analysis following published human validation guidelines. Validation experiments investigated reproducibility, heteroplasmy, mixed DNA, DNA template concentration, chemical treatments, substrate variation, environmental conditions and thermocycling parameters. Sequence similarity searches using both GenBank BLASTn and BOLD search engines indicated that the COI gene consistently identifies species where authenticated reference sequence data exists. Where misidentification occurred the cause was attributable to either erroneous reference sequences from published data, or lack of primer specificity. Although amplification failure was observed under certain sample treatments, there was no evidence of environmentally induced sequence mutation in those sequences that were generated. A simulated case study compared the performance of COI and cytochrome b mtDNA genes. Findings are discussed in relation to the utility of the COI gene in forensic species identification.     

Behavior of genetic markers in recipients after bone marrow transplantation and problems in forensic medicine

The authors report studies on four pairs of donors and recipients in bone marrow transplantation (BMT). A broad range of gene markers at 41 gene loci, including 11 red blood cell markers, 5 human lymphocyte antigen (HLA) types, 12 serum protein markers, 5 red cell enzyme markers, and 8 salivary markers were evaluated before and after BMT over 2 months. As a result, 9 out of 41 gene loci of genetic markers in recipients were transformed into the donor type. BMT between family members may lead to transformation of gene markers, but within a pattern compatible with family inheritance patterns, and no genetic paradox will be found in later surveys of familial genetic relationships. However, in a personal identification system in forensic medicine using genetic markers as an index, the appearance of a phenotype incompatible with a blood relationship is possible after BMT with a non-blood-relative donor. This result is similar to the inheritance pattern observed after artificial insemination by a donor's semen (AID), a more complete out-of-family cross.     

Population data on the forensic genetic markers: phosphoglucomutase-1, esterase D, erythrocyte acid phosphatase and glyoxylase I

Blood specimens from white and black sample populations from Baltimore, Maryland, were analyzed for the four most forensically important, polymorphic red cell enzyme systems-phosphoglucomutase-1, esterase D, erythrocyte acid phosphatase and glyoxalase I. The distributions of the phenotypes for each marker in each racial group were in Hardy-Weinberg equilibrium. The population data were similar to previously reported data for Whites and Blacks from different geographical locations within the United States.     

Significance of mitochondrial DNA for forensic stain analysis, identification and forensic lineage determination

DNA testing using conventional STR systems may produce insufficient results, if the genomic DNA in the specimen is either highly degraded or the available quantity is very small (e.g. skin particles, hair shafts or ancient bones). In some of these cases the examination of mitochondrial DNA, which is present in considerably larger copy numbers in the cytoplasm, is more successful than that of nuclear DNA. Identification of unknown corpses by conventional DNA typing sometimes remains doubtful, if only samples from presumably distant relatives or putative brothers or sisters are available for comparison. Since mitochondrial DNA is generally transmitted in maternal lineages, its sequence pattern can be directly compared with those of other individuals and, in case of the same maternal lineage, corresponding sequence chromatograms are to be expected. In connection with nuclear DNA typing methods certain sequence motives may furnish clues to ethnic groups. The report presents three cases illustrating the application possibilities of mtDNA typing in forensic practice.     

Successful extraction of human genomic DNA from serum and its application to forensic identification

We report here on the successful extraction of human genomic DNA from a serum sample in a forensic case. The extracted DNA was successfully used for the identification of remains presumably immersed for more than three weeks for which the only comparison sample was a 250-microL serum aliquot kept frozen in a laboratory. The analysis made it possible to identify a second victim as the daughter of the first.     

A novel multiplex assay system based on 10 methylation markers for forensic identification of body fluids

Identifying the source of body fluids found at a crime scene is an essential forensic step. Some methods based on DNA methylation played significant role in body fluids identification. Since DNA methylation is related to multiple factors, such as race, age, and diseases, it is necessary to know the methylation profile of a given population. In this study, we tested 19 body fluid-specific methylation markers in a Chinese Han population. A novel multiplex assay system based on the selected markers with smaller variation in methylation and stronger tissue-specific methylation were developed for the identification of body fluids. The multiplex assay were tested in 265 body fluid samples. A random forest model was established to predict the tissue source based on the methylation data of the 10 markers. The multiplex assay was evaluated by testing the sensitivity, the mixtures, and old samples. For the result, the novel multiplex assay based on 10 selected methylation markers presented good methylation profiles in all tested samples. The random forest model worked extremely well in predicting the source of body fluids, with an accuracy of 100% and 97.5% in training data and test data, respectively. The multiplex assay could accurately predict the tissue source from 0.5 ng genomic DNA, six-months-old samples and distinguish the minor component from a mixture of two components. Our results indicated that the methylation multiplex assay and the random forest model could provide a convenient tool for forensic practitioners in body fluid identification.     

Analysis of genetic diversity of the mitochondrial DNA in the forensic medical expert identification of individuals

Spectra of haplotype frequencies were studied for locuses of hypervariable segments 1 and 2 (HVS1 and HVS2), separately for each, and for linked segment HVS1-HVS2. The obtained data were used to determine the values and to evaluate comparatively the discriminating characteristics of the corresponding individualizing systems based on the typing of mtDNA. The system of typing, based on HVS2 (mv = 0.098), was found to possess the least discriminating potential; while the highest information rate is ensured in the analysis of HVS1 (m omega = 0.02) and in the joint analysis of HVS1 and HVS2 (mw = 0.007). The frequency rates of the key haplogroups were estimated within a random sampling of Russian citizens. A random population sampling of Russian citizens was shown not to differ essentially from an ethnically homogeneous population sampling of Russians selected with regard for a genetic diversity and for a spectrum of mitochondrial lines. The results point at the most rational algorithm of examinations in a forensic expert's analysis of mtDNA. The studied sampling can trigger the development of a referential data base designed for conducting, in the Russian Federation, the forensic-medical expert's examinations based on the mtDNA typing.     

Personal identification and missing persons initiatives in Santa Catarina state,Brazil: forensic perspectives from 2019 to 2021

Santa Catarina is a small, developed, and relatively safe state in South Brazil. Despite having positive social economic indicators, it still faces multiple challenges regarding forensic practices for personal identification. The objective of this paper is to discuss the recent advances and current challenges in the region, from the perspectives of anthropological and dental postmortem human identification, missing persons, and disaster victim identification (DVI) from 2019 to 2021. The recent creation of a Forensic Anthropology Sector (SAF) in the state’s official forensic institution (Polícia Científica—PCI) has significantly improved identification of unidentified remains and optimised resources available for DNA analysis. However, SAF is still quite understaffed, which negatively affects the recovery of skeletal material, its preparation, and the time needed for filing reports. Santa Catarina has passed legislation for missing persons in 2015, 4 years prior to the sanction of federal laws implementing the national policy for the disappeared. Nonetheless, a lack of integration between stakeholders remains a problem that PCI has tried to circumvent with the Conecta Programme, a multidisciplinary and integrated initiative between families of the missing persons, police agencies, and the Public Ministry. The programme aims to collect not only reference DNA samples, but also relevant anthropological and dental data. It also offers facial progression services in cases of disappearances that occurred many years ago. Despite a history of disasters in the state, PCI still needs to implement international DVI standards at an institutional level. Recent training on Phase 1 DVI procedures, integrated with other responding institutions, indicates better preparation for future disasters. There are many challenges ahead for Santa Catarina’s forensic institution and professionals that have yet to be addressed, but the overall situation on routine personal identification, missing persons initiatives, and DVI has improved over the last 2 years.     

光谱成像在物证检验中的初步实验研究

目的研究运用光谱成像技术进行物证形态检验的可能性和方法。方法比较相同条件下使用普通照相方法与光谱成像方法拍摄多种痕迹物证的效果。结果光谱成像检验的能力和效果都具有明显优势。结论光谱成像检验技术的出现使物证形态检验学的发展进入了一个崭新的阶段。     

Application of species-specific polymerase chain reaction in the forensic identification of tiger species

Globally, tigers are considered to be endangered, and are listed on Appendix I of CITES. A simple test, using a species-specific primer pair, was developed to identify tiger meat, faeces and dried skin, and provide forensic evidence of illegal wildlife trade. The specific fragment of mitochondrial cytochrome b gene was also successfully amplified from raw DNA products extracted from single tiger hairs. This PCR-based approach opens a new avenue to forensic identification of less-than-optimal samples.