Research Progress of Exosomes and Their Forensic Significance / 法医学杂志

Exosomes are membranous tiny vesicles secreted by cells, which are widely found in the extracellular matrix and various body fluids and carry a variety of biologically functional molecules such as proteins, lipids, messenger RNA (mRNA) and microRNA (miRNA). Exosomes not only play important biological roles in the field of immunology and oncology, but also have potential application value in the field of forensic medicine. This article reviews the discovery, production and degeneration mechanism, biological functions, isolation and identification methods of exosomes, summarizes the research on exosomes and their significance in the field of forensic science, and discusses their applications in body fluid identification, individual identification, postmortem interval estimation to provide ideas for the application of exosomes in forensic work.

New Advances, Challenges and Opportunities in Forensic Applications of Microbiomics / 法医学杂志

The succession of microbiota is closely associated with several essential factors, including race, sex, health condition, lifestyle, postmortem interval, etc., and it has great potential application value in forensic medicine. This paper summarizes recent studies on the forensic applications of the microbiome, including individual identification, geographical feature identification, origin identification of the tissue or body fluid, and postmortem interval estimation, and introduces the current machine learning algorithms for microbiology research based on next-generation sequencing data. In addition, the current problems facing forensic microbiomics such as the extraction and preservation of samples, construction of standardization and database, ethical review and practical applicability are discussed. Future multi-omics studies are expected to explore micro ecosystems from a comprehensive and dynamic perspective, to promote the development of forensic microbiomics application.

Research Progress on the Application of Human Oral Microbiome in Forensic Individual Identification / 法医学杂志

The oral cavity is the second largest microbial bank in humans after the intestinal canal, colonizing a large number of microorganisms including viruses, bacteria, archaea, fungi and protozoa. The great number of microbial cells, good DNA stability, and individual has a unique microbial community, these characteristics make the human microbiome expected to become a new biomarker for forensic individual identification. This article describes the characteristics of human oral microorganisms and microbial molecular markers in detail, analyzes the potential application value of microorganisms in forensic individual identification, and reviews the research progress of human oral microorganisms in forensic individual identification.

Individual Identification in Facial Appearance Biometrics Based on Macroscopical Comparison / 法医学杂志

Individual identification is one of the research hotspots in the practice of forensic science, and the judgment is usually built on the comparison of the unique biological characteristics of the individual, such as fingerprints, iris and DNA. With the dramatic increase in the number of cases related to video image investigations, there is an increasing need for the technology to identify individuals based on the macroscopic comparison of facial appearance biometrics. At present, with the introduction of computer three-dimensional (3D) modeling and 3D superimposition comparison technology, considerable progress has been made in individual identification methods based on macroscopic comparison of facial appearance biometrics. This paper reviews individual facial appearance biometric methods based on macroscopical comparison, comprehensively analyzes the advantages and limitations of different methods, and puts forward recommendations and prospects for subsequent research.

Establishment of Multiplex Amplification System of STR Loci in Felis Catus and Its Forensic Application / 法医学杂志

OBJECTIVES@#To construct a Felis catus STR loci multiplex amplification system and to evaluate its application value by testing the technical performance.@*METHODS@#The published Felis catus STR loci data were reviewed and analyzed to select the STR loci and sex identification loci that could be used for Felis catus individual identification and genetic identification. The fluorescent labeling primers were designed to construct the multiplex amplification system. The system was validated for sensitivity, accuracy, balance, stability, species specificity, tissue identity and mixture analysis, and investigated the genetic polymorphisms in 145 unrelated Felis catus samples.@*RESULTS@#Sixteen Felis catus autosomal STR loci and one sex determining region of Y (SRY) were successfully selected, and constructed a multiplex amplification system containing the above loci. The complete profile of all alleles could still be obtained when the amount of DNA template was as low as 0.25 ng. There was no specific amplification peak in other common animal samples. Population genetic surveys showed that total discrimination power (TDP) of the 16 STR loci was 1-3.57×10-20, the cumulative probability of exclusion (CPE) was 1-6.35×10-5 and the cumulative probability of matching was 3.61×10-20.@*CONCLUSIONS@#The Felis catus STR multiplex amplification system constructed in this study is highly sensitive, species-specific, and accurate in typing results, which can provide an effective solution for Felis catus species identification, individual identification and kinship identification in the field of forensic science.

Research Progress on Computer-Aided Skeleton-Based Individual Identification in Forensic Radiology / 法医学杂志

Individual identification based on imaging data of the skeleton of a corpse is a key technique for forensic identification. To reduce the influence of artificial factors, computer-aided semi-automatic or automatic individual identification has become one of the research directions of skeleton-based individual identification in forensic radiology. Therefore, this paper reviews and summarizes literatures related to estimation of anthropological information such as, age and sex by computer-aided forensic radiology bone characteristics and individual identification based on bone imaging characteristics, in order to provide reference on skeleton-based individual identification in forensic radiology.

Research Progress on Individual Identification by Frontal Sinus Imaging / 法医学杂志

Frontal sinus imaging is an important research object in forensic individual identification due to the highly specific irregular air cavity shape of frontal sinus, the stability of its shape after maturity, and the wide clinical application of radiology technology. The use of frontal sinus imaging for individual identification has significance in the court. When the application of traditional individual identification methods such as fingerprint identification and DNA analysis are limited or cannot be effectively carried out, or when the corresponding dental records are lacking and in other special cases, individual identification with frontal sinus imaging comparison is an effective alternative. Various types of image data can be used for individual identification with frontal sinus, mainly based on artificial visual comparing. With limitations such as, high professional requirements, low efficiency and small application range, the methods cannot be used in mass disasters. In recent years, some computer image recognition techniques have been used in identification of frontal sinus imagings and can significantly improve the efficiency of recognition. Difficulties such as low manual recognition efficiency may be overcomed. This study summarizes the reports on forensic individual identification using frontal sinus imaging, to review the research progress on individual identification with frontal sinus imaging, to provide a reference for further research on frontal sinus imaging, and to provide ideas for exploration and establishment of a faster, more efficient and more accurate individual identification system.

The Region of Interest in Boundary Calibration for Palatal Ru-gae Image of Forensic Identification / 法医学杂志

Objective To examine the method of least-square fitting for calibrating the palatal rugae boundary. Methods According to the distribution of the teeth, the feature points were selected; when they were fit, the boundary of the palatal rugae area was created, thereby constructing a mask. The mask was used to remove the part located outside the boundary and filter out the interference. Three samples were utilized for the ex-periments and analyses to come. Results To evaluate the quantitative results of the fitting curves, the correla-tion coefficients(r)of the samples and the relationship between the actual mean value and ideal mean value was obtained through six fitting processes. The differences between the actual mean and ideal mean were found to be significantly small (from 0.2857 to 2.5000) in the six fitting processes, with the range of r close to 1(from 0.9896 to 0.9995). Conclusion The effect of the cubic polynomial fitting method adopted in this study was stable.The proposed boundary calibration method can effectively locate the palatal rugae boundary and remove the interference area, further promoting the practice of forensic identification.

Sex Characteristics and Distribution of External Ear in Uygur Population of Xinjiang / 法医学杂志

Objective To analyze the characteristics of the bilateral external ears of Uygur adults by directly observing the morphological characteristics of the external ears of Uygur adults and classifying each feature. The frequency distribution of the characteristics was calculated to provide reference for forensic identification. Methods The 210 cases （75 males and 135 females） of bilateral external ear photos of Uygur adults in Xinjiang that met the inclusion criteria were collected. The frequencies of the features of the external ear were recorded and distinguished between the two sexes and the different sides. The data were statistically analyzed by SPSS 21.0 statistical software. Results The shapes of the external ears of males and females were commonly oblique or rectangular （34.67% of the left external ear of males and 41.33% of the right were oblique; 30.37% of the left and right external ear of females were rectangular）, while triangular ears were the rare variants and the least common. Sex and bilateral differences were observed as regards the form of the helix in the subjects. Normally rolled helix was the most common （58.67% males and 61.48% females for the left ear; 60.00% males and 72.59% females for the right ear）. Wide covering scapha helix was the most rare for the male left ear and flat helix was the most rare for the female right ear. Square and free earlobes were the most common （49.33% males and 62.96% females for the left ear; 40.00% males and 54.81% females for the right ear）, whereas triangular earlobes were rarely seen. Single knob tragus （40.00% males and 37.78% females for the left ear; 37.33% males and 33.33% females for the right ear） and projection type of Darwin's tubercle （50.67% males and 40.00% females for the left ear; 48.00% males and 39.26% females for the right ear） were found to be common. Conclusion The characteristics of the bilateral external ears of male and female Uygur adults have differences, which can be used for forensic identification.

Genetic Polymorphism and Forensic Application of 47 Autosomal InDel Loci in 5 Chinese Ethnic Groups / 法医学杂志

Objective To investigate the population genetic data of 47 autosomal insertion/deletion （InDel） polymorphism genetic markers involved in AGCU InDel 50 kit in Guangdong Han, Guangxi Zhuang, Guangxi Yao, Guangxi Jing, and Guangxi Mulam, and to evaluate their application in forensic DNA identification. Methods Multiplex amplification of the 768 unrelated individuals from the 5 ethnic groups mentioned above was performed with the AGCU InDel 50 kit. Genotyping was carried out by 3500xL gene analyzer, population genetic parameters were gathered and polymorphism analysis was performed. Results No linkage disequilibrium was found among 47 autosomal InDel loci in the 5 ethnic groups. The distribution of genotype frequency of 47 autosomal InDel loci confirmed to the Hardy-Weinberg equilibrium in Guangdong Han and Guangxi Zhuang. Except for rs139934789, the other 46 loci confirmed to the Hardy-Weinberg equilibrium in Guangxi Yao, Guangxi Jing, and Guangxi Mulam. The results of genetic variation analysis among the populations showed that 1.12% of genetic variation was caused by ethnic group differences. The cumulative discrimination power of 47 autosomal InDel loci for the 5 ethnic groups were all above 0.999 999 999 999 999. The cumulative probability of exclusion for each ethnic group was less than 0.999 9. The two Y-InDels were identified in all male individuals and were absent in all female individuals. Conclusion Except for rs139934789, the other 46 InDel loci have a relatively good genetic polymorphism in the 5 Chinese ethnic groups, and can be used for forensic individual identification and as effective supplements for paternity testing.

Research Progress on Discrimination of Monozygotic Twins / 法医学杂志

Individual identification plays an import role in the practice of forensic medicine, and often provides crucial evidence for the analysis and detection of criminal cases.However, for individual identification in complex situations, such as monozygotic (MZ) twins assumed to be genetically identical, it is impossible to distinguish one from the other by using traditional forensic DNA typing system.Therefore, how to discriminate the MZ twins has become and will continue to be one of the difficult problems in forensic field.This paper summarized the genetic and epigenetic changes recently identified in MZ pairs, which might provide a new insight to forensic discrimination of MZ twins.

Genetic Parameters of SNP Loci in Next Generation Sequencing Kits and Their Comparison / 法医学杂志

OBJECTIVES@#To calculate genetic parameters of SNP loci in next generation sequencing kits, and to compare them with STR loci for establishing the conversion ratio between SNP and STR system effectiveness.@*METHODS@#Hardy-Weinberg equilibrium tests were performed in 101 SNP loci of next generation sequencing kits （ForenSeq™ DNA Signature Prep kit and Precision ID Identity Panel kit）. The parameters of system effectiveness of SNP loci in the cases of personal identification, trios, duos, and alleged parents were calculated, which were compared with the genetic parameters of STR loci.@*RESULTS@#Except 2 loci without the data of genotype frequency, other 99 SNP loci conformed to Hardy-Weinberg equilibrium tests （P>0.05）. In ForenSeq™ DNA Signature Prep kit, the CDP of 94 SNP loci was 1-1.152 1×10⁻³⁴, CPEtrio was 1-4.416 9×10⁻⁸, CPEduo was 1-8.483 7×10⁻⁵, and CPEAP was 1-1.222 7×10⁻¹². In Precision ID Identity kit, the CDP was 1-2.052 4×10⁻³³, CPEtrio was 1-8.709 3×10⁻⁸, CPEduo was 1-1.163 8×10⁻⁴, and CPEAP was 1-3.725 7×10⁻¹². In the cases of personal identification, trios, duos and alleged parents, the system effectiveness of 2.85, 4.51, 4.88 and 4.55 SNP loci was equal to that of 1 STR locus, respectively.@*CONCLUSIONS@#With high system effectiveness of SNP loci, the next generation sequencing kits is suitable for personal identification and paternity testing in forensic science.

Individual Identification of Cartilage by Direct Amplification in Mass Disasters / 法医学杂志

Objective T o explore the effectiveness of direct am plification for the ST R analysis of carti-lage, and to accelerate the effectiveness of disaster victim identification. Methods E ighty-eight cartilage sam ples w ere directly am plified by Pow erPlex誖21 kit, and the results of genotyping w ere com pared w ith that obtained by the m agnetic beads m ethod. Results In 88 cartilage sam ples, the ST R genotypes w ere successfully detected from 84 sam ples by direct am plification and m agnetic beads m ethod, and both the results of genotyping by tw o m ethod w ere consistent. Conclusion D irect am plification w ith Pow er-Plex誖21 kit can be used for ST R genotyping of cartilages. T his m ethod is operated easily and prom ptly, w hich has a potential application in the individual identification of m ass disasters.

The research of individual identify by comparison of auricle / 中国法医学杂志

Objective To study the characteristics of measurement points in auricle and to make a method of individual identification by auricle. To make an accurate, simple and reliable individual identification recognition to forensic anthropology by the auricle in the videos and pictures. Methods To select measurement points by the auricle pictures of the 148 adults of Han nationality -from 19 to 22 years old- beyond one month and to analysis the data by SPSS statistical software, analyzing the various factors that influence on the measurement result, then to calculate the ability of recognition, and to confirm the each index difference and the reference value range between the two batch of photos in the end. Results The 6 measurement points were retained by statistical test from the 10 measurement points. The result is stable, and the variation coefficient of each index is not quite different. Conclusion To confirm reference range of the 6 observation points so that to determine whether the two auricle pictures belong to the same individual is accurate and feasible method.

The relationship between DNA methylation profile of peripheral blood and smoking / 中国法医学杂志

Objective To evaluate the potential application of separating smoking individuals from non-smoking ones by DNA methylation profiles from peripheral blood. Methods Human genome-wide DNA methylation data were downloaded from NIH GEOdata base. DNA methylation values from certain CpG sites were used to evaluate their significance between smokers and non-smokers by Student's T Test, as well as the clustering analysis. Results There are significant DNA methylation between smokers and non-smokers for certain CpGs. Conclusion Detection of methylation status from human peripheral blood can distinguish smokers from non-smokers.

Research Progress on Forensic Dentistry / 法医学杂志

Forensic dentistry is an interdiscipline of forensic m edicine and stom atology, w hich provides legal inform ation by collecting, testing and assessing the dental evidence scientifically. In this review , the present application of forensic dentistry has been described, such as the estim ation of age, sex, species, occupation and living habit, as w ell as the identification of individual, dom estic violence or abuse, w hich aim s to enrich and im prove forensic dentistry for m aking it be m ore useful in forensic m edicine even in juridical practice.

Research Progress on Forensic Dentistry / 法医学杂志

Forensic dentistry is an interdiscipline of forensic medicine and stomatology, which provides legal information by collecting, testing and assessing the dental evidence scientifically. In this review, the present application of forensic dentistry has been described, such as the estimation of age, sex, species, occupation and living habit, as well as the identification of individual, domestic violence or abuse, which aims to enrich and improve forensic dentistry for making it be more useful in forensic medicine even in juridical practice.

Individual Identification of Cartilage by Direct Amplification in Mass Disasters / 法医学杂志

OBJECTIVES@#To explore the effectiveness of direct amplification for the STR analysis of cartilage, and to accelerate the effectiveness of disaster victim identification.@*METHODS@#Eighty-eight cartilage samples were directly amplified by PowerPle® 21 kit, and the results of genotyping were compared with that obtained by the magnetic beads method.@*RESULTS@#In 88 cartilage samples, the STR genotypes were successfully detected from 84 samples by direct amplification and magnetic beads method, and both the results of genotyping by two method were consistent.@*CONCLUSIONS@#Direct amplification with PowerPlex® 21 kit can be used for STR genotyping of cartilages. This method is operated easily and promptly, which has a potential application in the individual identification of mass disasters.

Genetic Polymorphism of 20 Autosomal STR Loci in Yunnan Han Popolation / 昆明医科大学学报

Objective To study the genetic polymorphism of 20 autosomal short tandem repeats(STR)loci in Yunnan Han population. Methods The 20 STR loci(D3S1358,D1S1656,D6S1043,D13S317,Penta E,D16S539,D18S51,D2S1338,CSF1PO,Penta D,TH01,vWA,D21S11,D7S820,D5S818,TPOX, D8S1179,D12S391,D19S433 and FGA)which were included in the PowerPlexR21 System kit were genotyped in 1085 unrelated Han individuals living in Yunnan province using multiplex amplication. PCR products were separated and analyzed by the AB 3130 automatic genetic analyzer and GeneMapper ID v3.2 software. Forensic parameters of each locus were calculated by Modified-Powerstates software. Results All the studied loci except for TH01 and TPOX were highly polymorphic. The observed heterozygosity(Ho)ranged from 0.6130 to 0.8743. Match probability(PM)ranged from 0.0179 to 0.2030. Power of discrimination(DP)ranged from 0.7970 to 0.9821. Probability of exclusion(PE)ranged from 0.3067 to 0.7432. Paternity index(PI)ranged from 1.2919 to 3.9766. Polymorphism information content(PIC)ranged from 0.5598 to 0.8958. No deviation of the Hardy-Weinberg equilibrium was observed. Conclusion The studied 20 STR loci were highly polymorphic in Yunnan Han population and could be used in forensic individual identification and paternity testing practice.