The hair shaft, a metabolically inactive tissue, poses unique challenges for RNA detection and analysis. Characterizing stable, polymorphic hair shaft RNAs advances non-invasive gene studies and nucleic acid preservation insights. In this exploratory study, we demonstrate their retained diverse, stable RNAs (19, 407 mRNAs, 32, 978 lncRNAs, 6, 952 circRNAs) with genetic polymorphisms. We screened 455 polymorphic RNA-SNPs and developed a custom next-generation panel achieving exceptional discrimination power (1–2.88 × 10⁻⁴⁹) for individual identification from single or aged (≥3 years) hairs, with additional ethnic origin prediction inference capability. This transcriptomic resource advances understanding of post-transcriptional regulation in keratinized tissues and establishes hair shafts as a novel source for non-invasive genetic testing. Beyond analysis for non-nuclear biological evidence in forensics, our findings lay the foundation for clinical applications in dermatology and biomarker discovery, particularly for hair-associated disorders and nucleic acid preservation studies.

Authors

• Jiaqi Wang (School of Forensic Medicine,Shanxi Medical University, China)
• Bofeng Zhu (School of Forensic Medicine,Shanxi Medical University, China)
• Gengqian Zhang (School of Forensic Medicine,Shanxi Medical University, China)