Difference Analysis Based on 16S rRNA Sequencing of Different Soil Bacterial Communities / 法医学杂志

Objective To study the structure and differences of bacterial communities in different soils, and to explore the effectiveness of 16S rRNA sequencing in identification of different soil. Methods Soil samples from 7 places in Shanghai were collected, then bacterial genomic DNA were extracted from them. The fragments of hypervariable region from 16S rRNA sequences were sequenced with high-throughput sequencing techniques. The results were quantified or visualized with bioinformatics software. The differences in diversity and abundance among the three kinds of bacterial communities in soil samples from grassland, forests and beaches were compared and analyzed. Results The statistical differences that existed among the alpha diversity indexes of bacterial communities in soil samples of grassland, forests and beaches had statistical significance. The relative abundance and diversity of bacterial communities in these three kinds of soil were significantly different. Grassland soil had higher Acidobacteria abundance, forest soil had higher Proteobacteria abundance, beach soil had higher Actinobacteria abundance. However, the differences in soil bacterial communities in artificial grasslands, natural grasslands and industrial district grasslands did not have statistical significance. Conclusion 16S rRNA sequencing can effectively distinguish different soils. This method may be able to provide clues for first crime scene inference in criminal cases.

Efficiency Analysis of EX16+10Y Kit on Detection of the Uygur Population in Xinjiang Province / 法医学杂志

Objective To analyse the efficiency of EX16+10Y kit on the forensic detection of the Uygur in Xinjiang province. Methods The blood samples were extracted from 4620 male individuals of Uygur in Xinjiang province, and amplified by EX16+10Y kit. The typing of amplification products was per-formed by 3130xl genetic analyzer. Results The genotyping graphs of 15 autosomal STR loci and 10 Y-chromosomal STR loci from 4620 male individuals of Uygur in Xinjiang province were acquired completely. The genotype distribution of 15 autosomal STR loci was consistent with Hardy-Weinberg equilibrium. The heterozygosity, polymorphism information content and discrimination power of STR loci were 0.637-0.838, 0.580-0.860 and 0.811-0.978, respectively. There were 766 haplotypes in 10 Y -chro-mosomal STR loci. Conclusion The test results of EX16+10Y kit is accurate and trustworthy, which can simultaneously be used for the individual identification and the screening of paternal pedigree in practical work.

Establishment of DNA Genetic Marker Identification System for Plant Evidence / 法医学杂志

Objective To establish a species identification system based on DNA genetic markers for plant evidence. Methods Two hundred common plants in Shanghai were collected and identified by mor-phological characteristics. The primers of gene segments rbcL, matK, and ITS were designed and amplified. The PCR amplicon was detected by agarose gel electrophoresis. After the sequencing, the universality and the identification capacity of the three markers were evaluated. Results The success rate of amplifi-cation was in order of rbcL (99.5％) >matK (92.5％) > ITS (86.0％). The identification capacity of the combination of rbcL and matK was better than that of rbcL or matK, by which most plant species could be identified to the genus or higher. ITS was not suitable to be a unique marker because of its unstable result, but it still could be a powerful supplement. The identification capacity of the combination of rbcL, matK and ITS was higher than that of rbcL and matK, by which most plant species could be identified to the genus or lower. Conclusion The identification system with the combination of rbcL, matK and ITS as markers has excellent universality for plant evidence, which can distinguish most plant species to the genus or lower.

Progress in the 16S rRNA Gene Sequencing in Forensic Science / 法医学杂志

Forensic microorganism is one of the hotspots of forensic science research. Due to its conservatism and specificity, the 16S rRNA gene is found to be an ideal marker for forensic identification. With the rapid development of high throughput sequencing technology, the research on microorganisms has been gradually applied to many fields such as environment and health care. In the field of forensic science, the results of forensic microbiology research, represented by 16S rRNA gene sequencing, are also gradually applied to forensic practice, such as biological samples identification, individual identification, postmortem interval estimation, and regional inference, which not only provide clues for the investigation of cases but also complement and assist traditional methods. This paper describes the research methods and related sequencing technologies of 16S rRNA gene sequencing, summarizes its research progress, and discusses the application value and potential of 16S rRNA in forensic science.

Application of the Peak Area Ratio of STR Loci to Amelogenin Locus in the Estimation of DNA Degradation / 法医学杂志

OBJECTIVE@#To explore the change rules of peak area ratio of STR loci to Amelogenin (AMEL) locus (STR/AMEL), a sex-determining gene in DNA degradation, and to evaluate the application of STR/AMEL value in the estimation of DNA degradation degree.@*METHODS@#DNA was extracted from iliopsoas, and the variations of STR/AMEL value (Penta E/AMEL, Penta D/AMEL, FGA/AMEL) were analyzed after the artificial degradation was made by DNase I, and the changes of these three ratios of the iliopsoas naturally degraded in an outdoor environment were also analyzed. The regression curves were analyzed using the periods of DNA degradation and outside the body as the independent variable (x) and the STR/AMEL value as the dependent variable (y) and three curve equations under two conditions were established.@*RESULTS@#Both under the conditions of artificial and natural degradation, STR/AMEL value had a negative relationship with the degradation time. The relationship between STR/AMEL and degradation time can be well simulated by the cubic function. R2 was over 0.99 under controlled degradation condition and over 0.86 under natural degradation condition.@*CONCLUSION@#The STR/AMEL value (Penta E/AMEL, Penta D/AMEL, FGA/AMEL) is negatively related with the DNA degradation degree, which follows mathematical regression models strictly, and it might be applied to evaluate the DNA degradation degree.

Research Progress on Gene Alterations of Amelogenin Locus in Gender Identification / 法医学杂志

There are two kinds of amelogenin gene mutation, including mutation in primer-binding region of amelogenin gene and micro deletion of Y chromosome encompassing amelogenin gene, and the latter is more common. The mechanisms of mutation in primer-binding region of amelogenin gene is nucleotide point mutation and the mechanism of micro deletion of Y chromosome encompassing amelogenin gene maybe non-allelic homologous recombination or non-homologous end-joining. Among the population worldwide, there is a notably higher frequency of amelogenin gene mutations in Indian population, Sri Lanka population and Nepalese population which reside within the Indian subcontinent. Though amelogenin gene mutations have little impact on fertility and phenotype, they might cause incorrect result in gender identification. Using composite-amplification kit which including autosomal STR locus, amelogenin gene locus and multiple Y-STR locus, could avoid wrong gender identification caused by amelogenin gene mutation.

Identification of Vaginal Fluid Using Microbial Signatures / 法医学杂志

OBJECTIVES@#To investigate the specific microbial signatures in vaginal fluid.@*METHODS@#Vaginal fluid （16 samples）, saliva （16 samples）, feces （16 samples）, semen （8 samples）, peripheral blood （8 samples）, urine （5 samples）, and nasal secretion （4 samples） were collected respectively. The 16S rRNA genes of Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus iners, and Atopobium vaginae were amplified. PCR production was detected via a 3130xl Genetic Analyzer.@*RESULTS@#The detected number of Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus iners, and Atopobium vaginae were 15, 5, 8, 14, and 3 in all vaginal fluid samples, respectively. Lactobacillus crispatus and Lactobacillus jensenii existed specifically in vaginal fluid.@*CONCLUSIONS@#There is a potential application value to detect Lactobacillus crispatus and Lactobacillus jensenii for the identification of vaginal fluid.

Source Identification of Human Biological Materials and Its Prospect in Forensic Science / 法医学杂志

Source identification of human biological materials in crime scene plays an important role in reconstructing the crime process. Searching specific genetic markers to identify the source of different human biological materials is the emphasis and difficulty of the research work of legal medical experts in recent years. This paper reviews the genetic markers which are used for identifying the source of human biological materials and studied widely, such as DNA methylation, mRNA, microRNA, microflora and protein, etc. By comparing the principles and methods of source identification of human biological materials using different kinds of genetic markers, different source of human biological material owns suitable marker types and can be identified by detecting single genetic marker or combined multiple genetic markers. Though there is no uniform standard and method for identifying the source of human biological materials in forensic laboratories at present, the research and development of a series of mature and reliable methods for distinguishing different human biological materials play the role as forensic evidence which will be the future development direction.

Application of Ion Torrent PGM™ System in Detection of Fetal DNA in Maternal Plasma / 法医学杂志

OBJECTIVE@#To explore the feasibility of detecting of Y-STR of fetal DNA in maternal plasma using Ion Torrent PGM™ System.@*METHODS@#A total of 16 fetal DNA samples from maternal plasmas (8 cases from 38 weeks gestational age and 8 ones from 12 weeks) were prepared and a multiplex assay with 7 STR loci (DYS390, DYS391, DYS393, DYS438, DYS437, DYS456, DYS635) was designed for multiplex-PCR amplification. Using Ion Torrent PGM™ System, the results of Y-STR sequences and capillary electrophoresis were obtained and compared.@*RESULTS@#Y-STR specific alleles were detected in the maternal plasma of all the pregnant women having male babies of second and third trimester, which were higher than that detected by capillary electrophoresis. Consistent Y-STR genotypes were observed between fetal DNA from maternal plasma and genomic DNA from the newborn babies.@*CONCLUSION@#Based on Ion Torrent PGM™ System, the prenatal Y-STR detection method may provide a high-sensitive and high-throughput choice for prenatal STR detection in forensic testing.

Progress in Association between Genetic Correlation and Human Violent Behavior / 法医学杂志

Human violent behavior is a complex behavior which is influenced by genetic and environmental factors. There is a trend in investigating the mechanism of violent behavior by using the genetic methods. This article reviews several candidate genes and advances in epigenetics which are associated with violent behavior. The prospects and significance of violent behavior research from the view of gene polymorphism and epigenetics are also discussed.

Development of a Forensic Multiplex Amplification STR Kit for 15 Autosomal STR Loci and 10 Y-STR Loci / 法医学杂志

OBJECTIVE@#To establish a multiplex STR genotyping method for autosomal STR and Y-STR loci in forensic biological practice.@*METHODS@#Widely used autosomal STR loci and Y-STR loci were selected. A set of PCR primers was designed, and a 5-dye fluorescent labeled STR multiplex PCR reagent kit was developed.@*RESULTS@#A kit was developed which can simultaneously detect 15 autosomal STR loci, 10 Y-STR loci, and an Amelogenin.@*CONCLUSION@#The 15 autosomal STR plus 10 Y-STR kit in combination with capillary electrophoresis method was used to STR genotyping with accurate and reliable results. The new one-step testing kit can potentially be widely used in forensic cases and DNA databank in the future.

Allele-specific PCR and its application in forensic science / 法医学杂志

Allele-specific polymerase chain reaction (AS-PCR) is a technique based on allele-specific primers, which can be used to analyze single nucleotide polymorphism (SNP) effectively including the transition, transversion and insertion/deletion polymorphism and has been exploited in the study of diseases research, molecular diagnosis, and forensic biological evidence. The article systematically reviews the principle, the detection methods, improvement of AS-PCR, and its research updates in the fields of autosome, Y chromosome and mitochondrial SNP, as well as its application in forensic science.

AS-PCR assay for 20 mtDNA SNP typing and haplotype frequency / 法医学杂志

OBJECTIVE@#To develop a multiplex allele-specific PCR (AS-PCR) assay with three-color fluorescence labeling for mitochondrial DNA (mtDNA) SNP typing.@*METHODS@#Based on the principle of AS-PCR, the primer sets were designed for 20 SNP located on the coding region of mtDNA and divided into 2 groups labeled with FAM and HEX fluorescence, respectively. A primer set included two forward (reverse) allelic specific primers with different sizes and a generic reverse (forward) primer. Blood samples from 200 unrelated individuals were analyzed by AS-PCR and capillary electrophoresis. Three random samples at least for each SNP site were examined and verified by direct sequencing. The haplotype frequency was investigated.@*RESULTS@#Distinct electropherograms of 200 blood samples were obtained successfully. The typing results of direct sequencing were identical to those obtained from AS-PCR. The minimum detectable DNA concentration was 0.2 pg under the system of 10 microL. The sensitivity of the DNA concentrations ranged from 0.5 to 5 pg. The 200 individuals were assigned into 15 haplotype, and the haplotype diversity was 0.906 0.@*CONCLUSION@#AS-PCR is a simple, rapid and efficient method for mtDNA SNP typing, and can be applied to forensic practice.

Establishment of the multiplex genotyping system for 16 SNP loci on mtDNA / 法医学杂志

OBJECTIVE@#To establish a multiplex genotyping system of mtDNA SNP.@*METHODS@#A multiplex analysis system of 16-plex mtDNA SNP loci was established with allele specific PCR and capillary electrophoresis genotyping technology. Fifty samples from unrelated Chinese Han individuals were typed with the multiplex system. The multiplex assay was validated by comparing with the direct sequencing method.@*RESULTS@#The genotypes of all 50 samples were correctly determined by the multiplex system. The optimal genotypic graphs were obtained with an input DNA of 0.5-10 pg, and the typing results were completely consistent with those by direct sequencing method.@*CONCLUSION@#The established multiplex system by allele specific PCR has high sensitivity, operational simplicity and high accuracy. It provides an effective and high output method for mtDNA SNP typing.

Determination of the biological attribute of evidence at the scene using reverse transcription PCR and real-time fluorescent quantitative PCR / 法医学杂志

OBJECTIVE@#To explore the feasibility of biological method to identify the biological attribute of samples at crime scene.@*METHODS@#Thirty samples of ten blood stains, ten saliva stains and ten semen stains were selected, and all the samples were processed by the routine method and biomolecular method, respectively. Both RNA and DNA were isolated using DNA-RNA co-extraction technology and the mRNA was converted into cDNA using reverse transcription PCR (RT-PCR). Three pairs of specific primers were designed for blood stain, saliva stain and semen stain based on the different target genes in three specific tissues and the primers were amplified using real-time fluorescent quantitative PCR. The differences in these biological samples were evaluated by melting temperature (Tm) values and the size of the amplification fragment.@*RESULTS@#The Tm values of blood stain, saliva stain and semen stain were (84.5 +/- 0.2) degrees C, (76.9 +/- 0.3) degrees C and (88.5 +/- 0.2) degrees C, respectively. The length of PCR fragments of them was 177bp, 134bp and 294bp, respectively.@*CONCLUSION@#Compared with the routine method, RT-PCR with real-time fluorescent quantitative PCR is highly specific, sensitive and reliable to identify the biological attribute of evidence, and can be potentially applied to determine evidence attribute in forensic practice.

Development of Chinese forensic Y-STR DNA database / 法医学杂志

Y chromosome is a male-specific paternal inherited chromosome. The STR markers on Y chromosome have been widely used in forensic practices. This article summarizes the characteristics of Y-STR and some factors are considered of selecting appropriate Y-STR markers for Chinese population. The prospects of existing and potential forensic applications of Y-STR profiles are discussed including familial excluding, familial searching, crowd source deducing, mixture sample testing, and kinship identifying. The research, development, verification of Y-STR kit, Y-STR mutation rate, and search software are explored and some suggestions are given.

Genotyping and parental related methylation of SNRPN gene rs220030 / 法医学杂志

OBJECTIVE@#To establish two methods by denaturing gradient gel electrophoresis (DGGE) and pyrosequencing for genotyping rs220030 (a SNP in the promoter region of small nuclear ribonucleoprotein polypeptide N, SNRPN). To establish an analytical technique for detecting CpG methylation status by pyrosequencing and to further investigate the feasibility of applying rs220030 to the determination of parental origin allele.@*METHODS@#The rs220030 of 97 blood samples from individuals of Shanghai Han population were genotyped by DGGE, meanwhile the rs220030 of 25 blood samples of them were genotyped by pyrosequencing to compare the two methods in genotyping SNP. Pyrosequencing united bisulfite conversion method was applied to detect CpG methylation status of region upstream rs220030 of two random blood genealogical samples and investigate whether the methylation status was parental related.@*RESULTS@#The rs220030 genotyping results of 97 blood samples detected by DGGE were 20 C homozygote, 29 T homozygote, and 48 C/T heterozygote. Twenty-five blood samples genotyped by pyrosequencing showed the same result with DGGE. The CpG methylation status of region upstream rs220030 of the child was similar to the mother.@*CONCLUSION@#Compared with DGGE, pyrosequencing is more accurate, convenient, and suitable for large samples and high throughput SNP genotyping. Pyrosequencing united bisulfite conversion can be used to detect CpG methylation status precisely. It is feasible to apply rs220030 to parental origin allele determination.

Forensic application of expressmarker 22 STR loci direct PCR amplification kit / 法医学杂志

OBJECTIVE@#To explore the application value of Expressmarker 22 STR loci direct PCR amplification kit.@*METHODS@#One thousand nine hundred and forty-eight samples (including samples spotted on FTA cards, filter papers and case samples) were tested using Expressmarker 22 STR loci direct PCR amplification kit. At the same time, all were tested using Sinofiler kit, Identifiler kit and PowerPlex 16 kit respectively for comparison. The genotypes were compared at the same STR loci among these four kits to test the sensitivity and accuracy of Expressmarker 22 STR loci direct PCR amplification kit.@*RESULTS@#97.79% samples were successfully typed using Expressmarker 22 STR loci direct PCR amplification kit. The genotype profiles of the same samples using Expressmarker 22 STR loci direct PCR amplification kit were consistent with Sinofiler kit, Identifiler kit and PowerPlex 16 kit at the same STR loci.@*CONCLUSION@#Expressmarker 22 STR loci direct PCR amplification kit can provide huge information and accurate results

Genetic polymorphisms of the dinucleotide STR locus D6S261 / 法医学杂志

OBJECTIVE@#To investigate the application of dinucleotide STR locus in paternity testing.@*METHODS@#Dinucleotide STR locus D6S261 was selected and the paternity testing blood samples were amplified using 200 random blood samples, 16 family samples and 193 paternity test samples. Data of the PCR products were collected by 3130XL Genetic Analyzer and the genetic parameters of population were calculated by PowerStats v12.@*RESULTS@#Fifteen alleles and 50 genotypes were found and H, DP, PE and PIC were 0.850, 0.953, 0.695, and 0.820, respectively. The typing results of both family samples and paternity test samples were accord with the law of inheritance, which no mutation was discovered.@*CONCLUSION@#The genetic polymorphisms of D6S261 show good characteristics with low mutation rate and high stability. It can be an effective method to solve the indetermination caused by mutation in paternity testing if the stutter bands can be decreased.

Rapid DNA identification using 6+1 STR kit and EX-Q20 electrophoresis / 法医学杂志

OBJECTIVE@#To establish a rapid STR genotyping method for individual identification.@*METHODS@#Two hundred blood samples from FTA were collected. Equal amount of blood were collected by puncher and analyzed using two methods (6+1 STR kit in combination with EX-Q20 electrophoresis and Sinofiler kit in combination with POP4 electrophoresis). Consuming time and results of two methods were compared.@*RESULTS@#6+1 STR kit in combination with EX-Q20 electrophoresis method can obtain all genotyping results and be shorter time.@*CONCLUSION@#6+1 STR kit in combination with EX-Q20 electrophoresis method is used to STR genotyping with accurate, reliable results and this new method is potential value in mass personnel investigation and comparison in major criminal cases. It also can raise the work efficiency.