Search

The identification of menstrual blood (MB) and peripheral blood (PB) left at a crime scene is crucial for crime reconstruction, especially in sexual assaults. MicroRNAs (miRNAs), a class of non-protein coding molecules, have been demonstrated to be a viable tool for body fluid identification in forensic casework. Several groups have searched for miRNAs that are specific to different body fluids. Blood has been studied the most extensively. However, menstrual blood was only involved in five studies, and the results confirming the presence of specific miRNAs could not be reproduced in other studies. In this study, we attempted to screen new markers that can differentiate between menstrual blood and peripheral blood by using Exiqon’s miRCURY™ LNA Array. Five miRNAs were selected based on the microarray results, namely, miR-141-3p, miR-373-3p, miR-497-5p, miR-143-5p, and miR-136-5p, whose expression levels exhibited 27.95-, 17.96-, 16.74-, 10.14-, and 9.21-fold changes, respectively, compared to the level in peripheral blood. Two classic quantitative methods, TaqMan hydrolysis probes (TaqMan for short) and SYBR Green fluorochrome (SYBR Green for short), were applied in the confirmation step to study the impact of different quantitative methods on the results. Three miRNAs (miR-141-3p, miR-497-5p, and miR-143-5p) were confirmed by TaqMan and one (miR-141-3p) by SYBR Green. Furthermore, bioinformatic methods were applied to interpret the candidate miRNAs. Our results established a multi-step procedure for body fluid identification and showed that the choice of quantitative method is important when miRNAs are used to identify the origin of blood samples. [ABSTRACT FROM AUTHOR]

A set of CpG sites were detected and evaluated to identify body fluids based on DNA methylation using the amplification refractory mutation system-PCR (ARMS-PCR). In this research, two multiplex DNA methylation reactions composed of four promising CpG sites were used for the identification of forensic regular body fluids. ARMS-specific primers were used to amplify the CpG sites and the methylation values of each CpG site were detected by capillary electrophoresis. The DNA methylation profiling of four highly informative candidate CpG sites was consistent with previously reported results. It is the first time to apply the ARMS-PCR to detect DNA methylation in forensic science, which provides a new method for forensic body fluid identification. We proved this method will have great potential in detection of the methylation profiling at molecular level. [ABSTRACT FROM AUTHOR]

RNA molecules, including mRNAs and microRNAs (miRNAs), have been used for forensic body fluid identification. Specific body fluids present unique mRNA expression patterns, while miRNAs identifying body fluids are mainly differentially expressed. miRNAs are thought to be more stable than mRNAs, although this lacks adequate supporting data. In this study, we addressed perceived concerns regarding the stability of miRNAs and mRNAs in blood samples. The samples used in this study involved three groups. First, environmentally-degraded blood stain samples were exposed to a range of environmental conditions over 1–360 days to degrade naturally. Second, simulated-degraded samples were prepared using RNase A or high temperature (80 °C). Furthermore, two authentic casework samples that were proven to be degraded from short tandem repeat (STR) profiles were analyzed. mRNAs and miRNAs present in the same blood samples were simultaneously detected through reverse transcriptase qPCR (RT-qPCR). Furthermore, mRNAs expression was determined by an mRNA multiplex PCR system. Our results showed that both mRNAs and miRNAs were stable in dry environments. The stability of miRNAs was relatively higher than that of mRNAs in humid environments or at high temperature. RNase A had the most serious impact on RNA stability, both mRNA profiles and miRNAs expression patterns were altered. The results of this study provide data and support to demonstrate that miRNAs represent more stable RNA molecules in body fluid identification compared to mRNAs. • This study evaluates mRNAs and microRNAs stability in blood samples. • Blood samples were degraded to various degrees in different ways. • Relative humidity and RNase A disrupt the stability of both microRNAs and mRNAs. • mRNA species are more vulnerable to humidity and heat than microRNAs. • Our study confirmed miRNAs could represent an important supplement to mRNAs for BFI. [ABSTRACT FROM AUTHOR]

In the past decades, mRNA marker has been well demonstrated the remarkable progress and wide application for its high sensitivity, specificity and robustness. However, according to previous studies, infertility has become a global health problem. Therefore given the increasing occurrence of male infertility, forensic researchers have to consider the impact of semen infertility on semen identification. In present study, normal semen (NS) asthenospermia (AS) and oligospermia (OS) semen samples were collected. The expression of semen-specific mRNA markers (KLK3, PRM1) was detected using end-point PCR. The results showed that KLK3 was almost not influenced by infertile semen samples. In contrast, PRM1 couldn't be detected in all the infertile semen samples, indicating that it may not be ideal mRNA marker to identify semen samples. The present study aimed to explore the effect of the infertile semen on body fluid identification and to identify semen-specific mRNAs. [ABSTRACT FROM AUTHOR]

Facial morphology is the most distinguishable appearance and represents a promising subfield of Forensic DNA phenotyping. Located in the center of the face, eyes are important for facial recognition. In this study, epicanthal fold and palpebral fissure were selected for a preliminary genotype-phenotype analysis. Two SNPs were genotyped with SNaPshot method in 156 Chinese Han adults. A significant increased incidence of high ratio of palpebral fissure width to height was observed in the populations with AG genotype for SNP rs2074612 on gene HBEGF: AG versus GG, OR = 2.36, 95%CI = 1.08–5.18, p <0.05; AG versus GG/AA, OR = 2.07, 95%CI = 1.03–4.16, p < 0.05. No significant genotype difference was detected between epicanthal fold positive/negative populations for both SNPs (p > 0.05). Further study including more samples should be conducted to discover SNPs associated with epicanthal fold and palpebral fissure traits. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) have been of interest in forensic science for body fluid identification with recent years. However, there is no study investigating the species specificity of miRNA markers by the SYBR Green method. Due to the conservation of miRNAs across species, miRNA markers maybe less species-specific than mRNA markers, and in forensic cases, animal buccal swabs are more likely to appear. Therefore, in this study we addressed the influence of 8 kinds of animal buccal swabs on human saliva, semen, vaginal secretion swabs and blood identification with 10 candidate specific miRNA markers by the SYBR Green quantitative PCR. Our data showed that the expression levels of the candidate specific miRNA markers miR-124a and 372 in the cat, dog, mouse and rabbit buccal swabs were in the same range as the human vaginal secretion swabs; buccal swabs from these animals also showed similar expression levels to human saliva for the candidate specific miRNA markers miR-200c, 205 and 658. These results indicated that biomaterials of buccal swabs from cats, dogs, mice and rabbits may be mistaken for human saliva or human vaginal secretion swabs, both of which could result in false positives for human body fluids. Thus, the interpretation of these miRNA profiles for human body fluid identification can be inaccurate in the presence of these animal buccal swabs. Therefore, we suggested performing species tests before human body identification with miRNA markers. [ABSTRACT FROM AUTHOR]

MicroRNA (miRNA) has attracted wide interest of the forensic community since Hanson attempted to search specific microRNAs for body fluid identification from microarray. Research groups have screened out some sets of miRNA markers that can be used in forensic body fluids identification up to now. Most of those miRNA markers could not be repeated in different labs. The markers confirmed by SYBRgreen always could not be confirmed by another group in Taqman. Different reverse-transcription quantitative PCR methods might be the major cause of that. To seek out the influences of different reverse-transcription quantitative PCR methods on the expression of miRNA, we chose three miRNAs which showed conflicted or consistent results in different RT-qPCR methods according to previous studies, including miR-412-3p, miR-124a-3p, miR-10b-5p, for menstrual blood, vaginal secretions and semen respectively. MiRNAs were analyzed through Taqman and SYBRgreen according to the protocols respectively. Different ΔCq values of the same miRNA marker were detected by SYBRgreen and Taqman. Different results can be attributed to the sensitivity and specificity of two reverse-transcription quantitative methods. The choice of appropriate reverse-transcription quantitative method should be based on the study targets and the conditions of samples. [ABSTRACT FROM AUTHOR]

DIPs (insertion/deletion polymorphisms) combining the advantages of both SNPs (single nucleotide polymorphisms) and STRs (short tandem repeats) show a great value in forensic case works. A high sensitive 21 AIM (ancestry informative markers)-DIPs panel developed by Daniel et al. is sufficient to distinguish between three major global population groups. However, Chinese population was not included in Daniel’s research. In this study, DNA samples from three Chinese population groups living in west of China (Han ( n = 60), Uighur ( n = 60) and Tibetan ( n = 60)) were extracted and analyzed following Daniel’s procedure. The difference in biogeographic ancestry between the three Chinese population groups was compared. The consequence shows no significant difference between Chinese Han, Uighur and Tibetan populations. In summary, this 21-plex DIP panel is unable to distinguish the three Chinese populations. To characterize three groups in China, more AIM-DIPs are needed. [ABSTRACT FROM AUTHOR]