MicroRNA as Biomarkers in Forensic Applications

MicroRNA (miRNA) analysis has been the focus of many researcher’s attention in the biomedical field since its discovery in 1993; however, the forensic application of miRNA analysis has only been suggested within the last 10 years and has been gaining considerable traction recently. MicroRNAs (miRNAs) are a class of small, endogenous, non-protein-coding RNA molecules of approximately 22 nucleotides in length, and exist extensively in a variety of eukaryotic cells.

MiRNAs regulate gene expression and play fundamental roles in multiple biological processes, including cell differentiation, proliferation, and apoptosis as well as aging and disease processes. MiRNAs have been shown to have high tissue specificity, resistance to degradation as a result of their small size and storage in the exosomes. They have no splicing variants unlike mRNA and their expression also follows a cell-specific pattern. Thus, they have great advantages for identifying forensically relevant body fluids.

Actually, recent studies have reported that several microRNAs are highly expressed in forensically relevant body fluids and can roughly distinguish semen, blood, saliva, and vaginal secretion. Body fluid identification is crucial in forensic casework for the reconstruction of the criminal activity. It may indicate how the sample was left at the crime scene.

For example, saliva may have been deposited by chatting while semen may be attributable to sexual assault. The personal identification is also useful for distinguishing the twins. Monozygotic twins are widely regarded as genetically identical, and traditional DNA typing methods are insufficient in identifying MZ twins. So, the discrimination of MZ twins becomes a forensic problem.

The studies’ results demonstrated that there are differences in the expression of miRNAs within MZ twin pairs, suggesting a role of miRNAs in identifying MZ twins. Similar to body fluid identification, the identification of certain internal organ tissues can be useful in the investigation of a violent crime. During a violent act, internal organ tissue may be transferred from the victim to the perpetrator, or to the weapon or innocuous item present, or to the location/scene at which the crime is being committed. Internal organ tissues may adhere to a bullet passing through a body, or to a knife

that has penetrated the skin. As miRNAs have shown great promise for body fluid identification, it is logical to infer that the same potential to their use for organ tissue identification, such as the brain, kidney, liver, lung, skin, heart muscle, and skeletal muscle. Anyway, further research into this novel application of miRNAs should be done.

There are, however, other forensic applications of miRNA profiling that have shown potential, yet are largely understudied, and warrant further investigation such as, donor age estimation, and more. Recent studies have focused on the application of DNA methylation for chronological age determination in the field of forensic genetics.

However, the amount of DNA and the complex bisulfite conversion process make applying this method in trace or degraded samples difficult. Human aging is an area of great interest, in particular with regards to identifying diagnostic predictors of age-associated diseases, such as cancer.

There is potential to translate the findings of biomedical research studies to forensic applications for estimating the age of a donor of a particular biological sample using miRNA analysis, especially for body fluids or stains at crime scenes. Recent developments in massively parallel sequencing (MPS) technology provide the opportunity to establish a whole-genome miRNA profile with high throughput and efficiency. Studies’ results demonstrated that the majority of miRNAs decreased in abundance with age. Anyway, the forensic application of microRNA analysis is only just being realized. As a result, published research in this area is limited, yet growing.


  1. Chao Xiao, Chao Pan, Erliang Liu, Huayu He, Chunfeng Liu, Yujie Huang, Shaohua Yi, Daixin Huang, Differences of microRNA Expression Profiles Between Monozygote Twins’ Blood Samples, Forensic Science International Journal, 2019; 41:152-158.
  2. Chen Fang, Jing Zhao, Junbo Li, Jialin Qian, Xu Liu, Qifan Sun, Wenli Liu, Yanjie Tian, Anquan Ji, Huijuan Wu, Jiangwei Yan, Massively Parallel Sequencing of microRNA in Bloodstains and Evaluation of Environmental Influences on miRNA Candidates Using Realtime Polymerase Chain Reaction, Forensic Science International: Genetics; 2019, 38:32-38.
  3. Chen Fang, Xu Liu, Jing Zhao, Bingbing Xie, Jialin Qian, Wenli Liu, Baoming Li, Xiaoli Zhang, Huijuan Wu, Jiangwei Yan, Age Estimation Using Bloodstain miRNAs Based on Massive Parallel Sequencing and Machine Learning: A Pilot Study, 2020, Forensic Sci Int Genet, 22;47:102300.
  4. Claire L Glynn, Potential Applications of microRNA Profiling to Forensic Investigations, 2020; RNA, 26(1):1-9.
  5. Dørum, G. et al. Predicting the origin of stains from whole miRNome massively parallel sequencing data, 2019, Forensic Science International: Genetics 40, 131–139.
  6. Landgraf, P. et al. A mammalian microRNA expression atlas based on small RNA library sequencing, 2007, Cell 129, 1401–1414.
  7. Mayes, C., Seashols-Williams, S. & Hughes-Stamm, S. A capillary electrophoresis method for identifying forensically relevant body fluids using miRNAs, 2017, Legal medicine (Tokyo) 30, 1–4.
  8. Morrison J, Watts G, Hobbs G, Dawnay N., Field-based detection of biological samples for forensic analysis: Established techniques, novel tools, and future innovations. Forensic Science International Journal, 2018; 285:147-160.
  9. Leary KR, Glynn CL., Investigating the Isolation and Amplification of microRNAs for Forensic Body Fluid Identification., 2018; Microrna, 7(3):187-194.
  10. Sauer E, Extra A, Cachee P, Courts C., Identification of organ tissue types and skin from forensic samples by microRNA expression analysis. Forensic Sci Int Genet., 2017; 28:99-110.
  11. Sauer, E., Reinke, A. K. & Courts, C., Differentiation of five body fluids from forensic samples by expression analysis of four microRNAs using quantitative PCR, Forensic science International: Genetics, 2016, 22, 89–99.
  12. Seashols-Williams, S. et al. High-throughput miRNA sequencing and identification of biomarkers for forensically relevant biological fluids, Electrophoresis, 2016, 37, 2780–2788.
  13. Shuntaro Fujimoto, Sho Manabe, Chie Morimoto, Munetaka Ozeki, Yuya Hamano, Eriko Hirai, Hirokazu Kotani, Keiji Tamaki, Distinct Spectrum of microRNA Expression in Forensically Relevant Body Fluids and Probabilistic Discriminant Approach, 2019, Scientific Reports, 4;9(1):14332.
  14. Sirker, M., Fimmers, R., Schneider, P. M. & Gomes, I. Evaluating the forensic application of 19 target microRNAs as biomarkers in body fluid and tissue identification, Forensic science International: Genetics, 2016, 27, 41–49.
  15. Taylor, D., Kokshoorn, B. & Biedermann, A. Evaluation of forensic genetics findings given activity level propositions: A review, Forensic Science International: Genetics, 2018, 36, 34–49.
  16. Valadi, H. et al., Exosome-mediated transfer of mRNAs and microRNAs is a novel mechanism of genetic exchange between cells, Nature cell biology 9, 2007, 654–659.
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