DNA methylation-based organ tissue identification: Marker identification, SNaPshot multiplex assay development, and...

Area of Science:

• Forensic Science
• Genetics
• Epigenetics

Background:

• Accurate identification of biological samples, such as organ tissues, is crucial for forensic investigations.
• Existing methods may lack the specificity or efficiency required for complex forensic casework.
• DNA methylation patterns offer a promising avenue for tissue-specific identification.

Purpose of the Study:

• To develop and validate a multiplex assay for the accurate identification of nine human organ tissues.
• To establish a reliable forensic tool for determining the origin of biological evidence.

Main Methods:

• Identification of organ tissue-specific CpG methylation markers using Illumina's methylation EPIC array data.
• Selection and validation of 18 hypomethylation markers for a SNaPshot assay.
• Design of two multiplex assays for accurate organ tissue origin determination.

Main Results:

• The developed multiplex assay achieved 100% accuracy in identifying nine organ tissue types in 88 Asian autopsy samples.
• Interlaboratory comparison with German autopsy samples showed 92.5% accuracy for eight organ tissue types.
• Minor discrepancies, such as off-target signals, were observed but could be mitigated by stringent thresholds.

Conclusions:

• The developed SNaPshot multiplex assays are highly accurate and valuable tools for forensic investigators.
• This technology aids in determining the organ origin of biological samples, supporting criminal investigations.
• The assay assists legal professionals in establishing crime scene circumstances through biological evidence analysis.