Identification of vaginal fluid, saliva, and feces using microbial signatures in a Han Chinese population.

In recent years, forensic scientists have focused on the discrimination of body fluids using microbial signatures. In this study, we performed PCR-based detection of microbial signatures of vaginal fluid, saliva, and feces in a Han Chinese population. We investigated the 16S rRNA genes of Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus iners, and Atopobium vaginae in vaginal fluid, the 16S rRNA and the glucosyltransferase enzyme genes of Streptococcus salivarius and Streptococcus mutans in saliva, and the 16S rRNA genes of Enterococcus species, the RNA polymerase β-subunit gene of Bacteroides uniformis and Bacteroides vulgatus, and the α-1-6 mannanase gene of Bacteroides thetaiotaomicron in feces.

[Application of Ion Torrent PGM™ System in Detection of Fetal DNA in Maternal Plasma].

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.

[Progress in Association between Genetic Correlation and Human Violent Behavior].

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.

[Development of a Forensic Multiplex Amplification STR Kit for 15 Autosomal STR Loci and 10 Y-STR Loci].

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.

[Allele-specific PCR and its application in forensic science].

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].

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.

[Establishment of the multiplex genotyping system for 16 SNP loci on mtDNA].

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.

[Determination of the biological attribute of evidence at the scene using reverse transcription PCR and real-time fluorescent quantitative PCR].

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).

[Development of Chinese forensic Y-STR DNA database].

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.

[Genotyping and parental related methylation of SNRPN gene rs220030].

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.

[Forensic application of expressmarker 22 STR loci direct PCR amplification kit].

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.

[Genetic polymorphisms of the dinucleotide STR locus D6S261].

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.

[Rapid DNA identification using 6+1 STR kit and EX-Q20 electrophoresis].

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).

[Forensic analysis of LCN DNA using sample concentration methods followed by miniSTR genotyping].

Objective: To optimize low copy number (LCN) DNA analysis methods for forensic STR genotyping.

Methods: Two groups of DNA sample, extracted using either Magnetic bead method or Chelex-100 methods, were previously amplified with a Identifiler PCR Amplification kit, but no genotype was detected. The DNA samples were concentrated using either a drying method or the Microcon-100 method, then amplified using an miniFiler PCR Amplification kit and genotyped.

[Determination of bloodstain formation time by RNA analysis].

Objective: To investigate the expression of 18S rRNA and beta-actin mRNA in bloodstain between 8 and 15 days after death and extrapolate the time of bloodstain formation.

Methods: RNA in dried bloodstain at different times was extracted, then quantified for 18S rRNA and beta-actin mRNA by real-time RT-PCR. The bloodstain formation time was deduced based on the changes of the ratio of 18S rRNA to beta-actin mRNA at different time points.

[Validation of Differential Extraction Kit in forensic sexual assault cases].

Objective: To evaluate the validity of Differential Extraction Kit in isolating spermatozoa and epithelial cell DNA from mixture samples.

Methods: Selective lysis of spermatid and epithelial cells combined with paramagnetic particle method were applied to extract the DNA from the mock samples under controlled conditions and forensic case samples, and template DNA were analyzed by STR genotype method.

Results: This Differential Extraction Kit is efficient to obtain high quality spermatid and epithelial cell DNA from the mixture samples with different proportion of sperm to epithelial cell.

[Application of MiniFiler kit in forensic DNA testing of low copy number template].

Objective: To detect low copy number of DNA samples by using a newly launched commercial miniSTR detection kit (MiniFiler) in forensic practice.

Methods: Low concentration and/or challenged forensic DNA samples were analyzed according to protocols provided by the manufacturer (Applied Biosystems, Foster City, USA).

Results: DNA samples as low as 10 pg could be amplified by MiniFiler kit, and the optimal DNA quantity was 40 pg or above.

[DNA genotyping of oral epithelial cells by laser capture microdissection].

Objective: The STR genotypping of trace oral epithelial cells which are microdissected by laser capture microdissection system (LCM) is explored.

Methods: The oral epithelial cells are microdissected using a low-power infrared laser by VERITAS Microdissection Instrument. STR loci of Profiler Plus are detected by multiplex PCR procesures.

[Study on application of the whole genome amplification in LCN].

Objective: To establish a method for whole genome amplification (WGA) based on (multiple displacement amplification MDA), and achieve DNA analysis of the human genome from low copy number (LCN).

Methods: DNA sample was used for WGA according to the REPLI-g kit protocol (QIAGEN, Germany). WGA product was used for DNA analysis according to the Applied Biosystems Profiler Plus kit protocol (ABI, USA).

[Effect of PCR reaction volume on the accuracy of human identification tests].

Objective: To investigate the effect of different PCR amplification volume on the accuracy of human identification test.

Methods: Human genome DNA samples were amplified using ABI PRISM Profiler Plus kits in 50 microliters, 25 microliters, 12.5 microliters, and 6.