Search

In the process of murder investigation, it is of great significance to find the discarded and buried human remains accurately. The main methods of searching for human remains include human visual search, aerial detection, geophysical technology, remote imaging technology and canine olfactory search technique. Canine olfactory search for human remains is a recognized time-effective and non-invasive search method, making dogs the most valuable search tool in forensic investigation. By systematically reviewing and summarizing relevant literature, and based on the theory of volatile organic compound produced by the decomposition of human remains, this paper explores the basic principle of the canine olfactory search technique for human remains. This paper also reviews the application of training canine search technique for human remains in forensic investigation by using human blood, tissue, cadaver putrefying fluid and odor substitutes as sniffing sources. The application prospect of canine olfactory search for human remains was prospected from the perspectives of detection of volatile organic compound during cadaver decay, development of odor substitutes and adsorption devices, and technology tactics used in canine training and use, to provide references for the relevant research of canine olfactory search for human remains in China.

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.

With the development of molecular biology and genomics, metagenomics is playing a more important role in forensic science and forensic identification. In recent years, as a branch discipline studying the composition profile and diversity of microbe flora as well as studying the interaction within microbe and with environment, the application of metagenomics has gradually risen and brought new opportunities for forensic identification-related area. In this review, strategy of metagenomics and its application in forensic identification including individual identification, origin determination of biological stain in crime scene and drug abuse detection are summarized. This article aims to elucidate the role and application value of metagenomics in forensic science., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine.)

Objectives: To analyze and detect the whole genome sequence of human mitochondrial DNA （mtDNA） by Ion Torrent PGM™ platform and to study the differences of mtDNA sequence in different tissues., Methods: Samples were collected from 6 unrelated individuals by forensic postmortem examination, including chest blood, hair, costicartilage, nail, skeletal muscle and oral epithelium. Amplification of whole genome sequence of mtDNA was performed by 4 pairs of primer. Libraries were constructed with Ion Shear™ Plus Reagents kit and Ion Plus Fragment Library kit. Whole genome sequencing of mtDNA was performed using Ion Torrent PGM™ platform. Sanger sequencing was used to determine the heteroplasmy positions and the mutation positions on HVⅠ region., Results: The whole genome sequence of mtDNA from all samples were amplified successfully. Six unrelated individuals belonged to 6 different haplotypes. Different tissues in one individual had heteroplasmy difference. The heteroplasmy positions and the mutation positions on HVⅠ region were verified by Sanger sequencing. After a consistency check by the Kappa method, it was found that the results of mtDNA sequence had a high consistency in different tissues., Conclusions: The testing method used in present study for sequencing the whole genome sequence of human mtDNA can detect the heteroplasmy difference in different tissues, which have good consistency. The results provide guidance for the further applications of mtDNA in forensic science., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine)

Matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF-IMS) has been a classical technique for studying proteomics in present and a tool for analyzing the distribution of proteins and small molecules within biological tissue sections. MALDI-TOF-IMS can analyze multiple unknown compounds in biological tissue sections simultaneously through a single measurement which can obtain molecule imaging of the tissue while maintaining the integrity of cellular and molecules in tissue. In recent years, imaging mass spectrometry technique develops relatively quickly in all biomedical domain. This paper based on the relevant data and reviews the present developing level of MALDI-TOF-IMS, the principle of imaging mass spectrometry, methology and the prospect in forensic pathology.

In the field of forensic science, conventional infrared spectral analysis technique is usually unable to meet the detection requirements, because only very a few trace material evidence with diverse shapes and complex compositions, can be extracted from the crime scene. Infrared microscopic technique is developed based on a combination of Fourier-transform infrared spectroscopic technique and microscopic technique. Infrared microscopic technique has a lot of advantages over conventional infrared spectroscopic technique, such as high detection sensitivity, micro-area analysisand nondestructive examination. It has effectively solved the problem of authentication of trace material evidence in the field of forensic science. Additionally, almost no external interference is introduced during measurements by infrared microscopic technique. It can satisfy the special need that the trace material evidence must be reserved for witness in court. It is illustrated in detail through real case analysis in this experimental center that, infrared microscopic technique has advantages in authentication of trace material evidence in forensic science field. In this paper, the vibration features in infrared spectra of material evidences, including paints, plastics, rubbers, fibers, drugs and toxicants, can be comparatively analyzed by means of infrared microscopic technique, in an attempt to provide powerful spectroscopic evidence for qualitative diagnosis of various criminal and traffic accident cases. The experimental results clearly suggest that infrared microscopic technique has an incomparable advantage and it has become an effective method for authentication of trace material evidence in the field of forensic science.

Objective: To compare the efficacy of three methods for forensic diatom test, namely strong acid digestion-centrifuge enrichment-light microscopy (SD-CE-LM), microwave digestion-membrane filtration-automated scanning electron microscopy (MD-ME-SEM), and microwave digestion-membrane filtration-light microscopy (MD-MF-LM)., Methods: Sixty samples were randomly divided into 3 groups for diatom test using three methods, and the sample preparation time, degree of digestion and recovery rate of diatoms were compared., Results: The sample preparation time was the shortest with MD-MF-LM and the longest with SD-CE-LM (P<0.05). MD-ME-SEM and MD-MF-LM allowed more thorough tissue digestion than SD-CE-LM. MD-ME-SEM resulted in the highest total recovery rate of diatom, followed by MD-MF-LM and then by SD-CE-LM (P<0.05); the recover rate of different diatom species was the highest with MD-ME-SEM, followed by MD-MF-LM and SD-CE-LM (P<0.05)., Conclusion: SD-CE-LM has a low recovery rate of diatoms especially for those with lengths shorter than 40 µm or densities less than 1/5. With a high recovery rate and accuracy in diatom test, MD-ME-SEM is suitable for diagnosis of suspected drowning cases. MD-MF-LM is highly efficient, sensitive and convenient for forensic diatom test.

To study the genetic diversities of 30 insertion-deletion (InDel) polymorphisms loci of Han population in Beijing, and to evaluate their forensic application, 210 unrelated healthy individuals of Han population in Beijing were investigated to determine the distributions of allele frequencies by using Investigator DIP system. The PCR products were detected with ABI 3130 XL Genetic Analyzer. Forensic parameters were calculated with relevant statistical analysis software. As a result, after the Bonferroni correction at a 95% significance level, there were no significant departures from Hardy-Weinberg equilibrium or significant linkage disequilibrium between the loci. The power of discrimination (DP) varies between 0.2690 (HLD118) and 0.6330 (HLD45), and the combined discrimination power (TDP) for the 30 InDel loci is 0.999999999985. The combined power of exclusion was 0.98771049 in trio cases (CPE(trio)) and 0.94579456 in duo cases (CPE(duo)). The parentage testing of 32 cases revealed no mutations happened to 30 InDel loci. Multiplex detection of the 30 InDel loci revealed a highly polymorphic genetic distribution in Beijing Han population, which represents a complementary tool in human identification studies, especially in challenging DNA cases.

Estimating postmortem interval (PMI) is always the emphasis and difficulty in forensic practice. Forensic entomology plays a significant indispensable role. Recently, the theories and technologies of forensic entomology are increasingly rich. But many problems remain in the research and practice. With proposing the Daubert standard, the reliability and accuracy of estimation PMI by forensic entomology need more demands. This review summarizes the application of the Daubert standard in several aspects of ecology, quantitative genetics, population genetics, molecular biology, and microbiology in the practice of forensic entomology. It builds a bridge for basic research and forensic practice to provide higher accuracy for estimating postmortem interval by forensic entomology.

microRNA (miRNA or miR) is a small single stranded non-coding RNA (21-25nt) that regulates gene expression in almost creatures. Currently, plenty of researches on how miRNA affects human cardiovascular disease have been reported. This review highlights recent findings about the role of miRNA in heart tissue and circulation correlated with human cardiovascular disease and explores the application of miRNA in sudden cardiac death in forensic science.

Objective: To establish an effective phenol-chloroform method coupled with paramagnetic particle method for human DNA extraction from maggot crop contents in STR genotyping., Methods: Human DNA was extracted from the maggot crop contents using phenol-chloroform method and purified by paramagnetic particle method. DNA was quantified by PCR with Quantifiler Human DNA Quantification Kit using 7500 real-time fluorescence quantitative PCR instrument. PCR products were genotyped by AmpFlSTR Identifiler PCR Amplification Kit using 3130XL-Avant genetic analyzer., Results: The template DNA yield by the method described were increased at least 2 times than the phenol-chloroform extraction method alone. All of the full 16 STR profiles could be obtained with the samples extracted by this method when the DNA yield reached (0.218 +/- 0.041) ng/microL., Conclusion: Phenol-chloroform method coupled with paramagnetic particle method can effectively increase the sensitivity of STR analysis of human DNA recovered from maggot crop contents and is a valuable tool for forensic entomology.

Genomic DNA was extracted from whole blood of 198 unrelated health individuals of Tujia ethnic group from south China's Hunan Province. Genotyping and detection of PCR products were carried out on denaturing polycrylamide gel electrophoresis followed by silver staining. Allele frequencies and genotype frequencies were computed. Deviation from Hardy-Weinberg equilibrium and differences of gene distribution were examined by SPSS 13.0. Fixation index, genetic polymorphism and indices of forensic application were calculated using Fstat and Powerstats, respectively. The results revealed that the frequencies of 65 alleles were distributed from 0.0048 to 0.6170. Among the ten X-STR loci, DXS6789, DXS6799 and HPRTB presented lower diversity and differentiation, while DXS7133 and DXS7423 showed lower value in forensic application. Results of multiple comparisons by loci showed that difference between German, Italian and Tujia population were the most dominant, and it suggested that great genetic differences did exist between Caucasian and Mongo-lian. In conclusion, DXS6804, DXS7132, DXS7130, DXS8378, DXS6789, DXS6799, DXS7424 and HPRTB had a good value in forensic identification, paternity testing of female and disease related study for Tujia population.

As it is a frequently encountered problem in the laboratory of forensic science nowadays to distinguish whether the questioned documents, such as deeds, contracts, and receipts, written in ballpoint pen inks are true or not, and identify the writing age of them, it is very essential to establish a simple, sensitive and accurate method to examine the similarities and differences of the ballpoint pen inks and identify the writing age. The present paper introduces a technique that allows identifying the kind and the writing age of the blue ballpoint pen inks. The technique is based on using a high performance liquid chromatographic method for distinguishing the similarities and differences in dyes of blue ballpoint pen inks and determining changes in dyes of blue ballpoint pen inks developed with age, and these changes can be evaluated by the ratio of peak areas.

Objective: To abtain the genetic polymorphisms data of eleven Y-chromosome STR loci in Yunnan Han population, and to evaluate its forensic application values, which will provide the base data for forensic application., Methods: DYS391, DYS389 I, DYS439, DYS389 II, DYS438, DYS437, DYS19, DYS392, DYS393, DYS390 and DYS385a/b loci were amplified by using Powerplex Y PCR amplification Kit and were analyzed by 310 genetic analyzer. 201 unrelated male individuals of Han population in Yunnan were investigated to determine the distributions of allele frequencies and haplotypes., Results: 3, 5, 6, 8, 5, 4, 5, 8, 4, 7 alleles were found across the Y-STR loci except DYS38556 haplotypes were found across DYS385a/b locus. The minimum GD value was 0.4273 (DYS438), and the maximum was 0.9747 (DYS385a/b). 175 haplotypes were found, of which 154 were unique, 16 were found in 2 individuals, 5 were found in 3 individuals, and the observed haplotypes diversity value was 0.9984., Conclusion: The 11 Y-STR loci are highly polymorphic and are suitable for forensic personal identification and paternity testing in Yunnan Han population.