Forensic validation of a combined analysis of mRNA and miRNA markers for precise tissue origin inferences of five kinds of body fluids by RT-qPCR

Classification of epidermal, buccal, penile and vaginal epithelial cells using morphological characteristics measured by imaging flow cytometry

As a result of the increased sensitivity of forensic DNA techniques, which can generate informative results from as little as a few cells, developing an understanding of the anatomical region these cells originate from is becoming more pertinent. Imaging Flow Cytometry (IFC) represents a promising method for identifying epithelial cells from different anatomical regions. This project aimed to determine whether IFC could be used to distinguish epithelial cells collected from different forensically relevant anatomical regions based on their morphology and autofluorescence. Penile, vaginal, buccal, and epidermal epithelial cells were collected in triplicate from 15 male and 15 female participants, in three different age groups: 18-39, 40-59, and 60+ years. Using the high statistical output from the IFC, 234 morphological measurements were collected for 571,546 single cells. Using a linear discriminate analysis with a minimum posterior probability threshold, the four epithelial cell types could be identified and distinguished with a 72-83 % classification accuracy. The results showed that the age and biological sex of the individual had no effect on the morphology of the four epithelial cell types. These data provide insights into the ability of IFC to identify and distinguish penile, buccal, vaginal, and epidermal epithelial cells and identifies further avenues for improvement and optimisation.

Forensic stability evaluation of selected miRNA and circRNA markers in human bloodstained samples exposed to different environmental conditions

Recently, RNA markers have been used to identify tissue origins of different kinds of body fluids. Herein, circRNA and miRNA markers were carried out to examine the presence or absence of peripheral blood (PB) in bloodstained samples exposed to different external environmental conditions, which mimicked PB samples left at the crime scenes. PB samples were placed on sterile swabs and then exposed to different high temperatures (37°C, 55°C and 95°C) and ultraviolet light irradiation for 0 d, 0.5 d, 1 d, 3 d, and 7 d, ultra-low and low temperatures (-80°C, -20°C, and 4°C) for 30 d, 180 d and 365 d and different kinds of disinfectants. Total RNA was extracted from bloodstained samples under the above different conditions, and the expressions of target RNAs (including miR16-5p, miR451a, circ0000095, and two reference genes RNU6b and 18 S rRNA) were detected by the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method. Results showed that these selected RNA markers could be successfully measured at all observation points with their unique degradation rates, which exhibited relative stability in degraded bloodstained samples exposed to different environmental conditions. This study provides insights into the applications of these studied miRNA and circRNA markers in forensic science.

Special Issue "Molecular Biology in Forensic Science: Past, Present and Future"

Molecular biology has always represented an enviable tool in the fields of biosciences, diagnostics, and forensic sciences [...].