AccScience Publishing / JBM / Online First / DOI: 10.14440/jbm.0231
RESEARCH ARTICLE

The last imprint: Differential methylation assay for forensic identification of brain tissue and death determination

Gal Bilinsky1 Dan Grinstein2 Anat Zvi1 Adi Beth-Din1 Ofir Israeli1*
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1 Department of Biochemistry and Molecular Genetics Institute for Biological Research, Ness Ziona, Central District 74100, Israel
2 Science & Technology Unit, Ministry of Defense, Hakirya, Tel Aviv 6473424, Israel
Submitted: 31 July 2025 | Revised: 9 September 2025 | Accepted: 25 September 2025 | Published: 14 November 2025
© 2025 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
Abstract

Background: The ability to test samples for the presence of specific tissues is useful for numerous forensic applications. More specifically, the identification of vital organ remains, such as the brain, in a crime scene or battlefield, can assist in determining the death of a missing person. In many cases, tissue samples are of insufficient quality or quantity for the application of histological methods, leaving forensic labs mostly restricted to immunological and catalytic assays designed to identify blood, semen, and saliva. Recent studies have suggested expression profiling-based methods for tissue and bodily fluid identification. Objective: We present a methylation-based assay for the detection of brain tissue in forensic samples. Methods: Genome-wide methylation data from 12 human tissues were analyzed to identify CpG sites uniquely methylated in brain tissue. Four candidate regions were selected based on high inter-tissue specificity and low intra-tissue variability. Targeted assays were developed using bisulfite conversion, polymerase chain reaction amplification, and next-generation sequencing, and validated based on reference tissues, mixtures, and environmentally degraded DNA samples. Results: Four regions displayed consistent brain-specific methylation with >94% single-read accuracy and complete sample-level discrimination at ≥5% brain DNA. The assay retained diagnostic performance in mixed and degraded samples, demonstrating robustness under typical forensic conditions. Conclusion: This study presents a sensitive and specific methylation-based assay for brain tissue identification. The approach enables reliable detection in degraded or composite materials and supports future integration of epigenetic biomarkers into forensic workflows for organ-source attribution.

Keywords
Bisulfite sequencing
Brain
Crime scene
DNA methylation
Genomics
High-throughput sequencing
Funding
None.
Conflict of interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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Journal of Biological Methods, Electronic ISSN: 2326-9901 Print ISSN: TBA, Published by POL Scientific