Raman spectroscopy can reliably determine biological sex from intact human dental enamel, offering a non-destructive alternative to DNA and proteomic methods, according to a new study.
The research team, based at the University of Zurich’s Institute of Evolutionary Medicine, explored whether molecular differences in enamel – arising from variations in the AMELX and AMELY proteins – could be detected using Raman spectroscopy. Enamel, the hardest and most durable biological tissue, retains trace biomolecular signatures over time and is frequently preserved in archaeological and forensic specimens.
Unlike prior approaches requiring destructive sampling of dentin or cementum, this study focused exclusively on the enamel surface of extracted human teeth. Spectra were collected from 88 teeth using a portable 785 nm Raman system. Analytical preprocessing ensured spectral consistency across samples, and statistical modeling was used to identify diagnostic features.
Multivariate modeling revealed distinct spectral patterns linked to biological sex. Orthogonal partial least squares discriminant analysis (OPLS-DA) highlighted strong separation between male and female samples, prompting the development of a simplified logistic regression model. This final model demonstrated excellent performance, correctly identifying sex in the majority of cases with a reported AUC of 0.98, a sensitivity of 0.87, and a specificity of 0.94.
“We hypothesize that Raman spectroscopy captures molecular fingerprints, which reflect variations between AMELX and AMELY isoforms,” the authors wrote, “thereby offering a promising, non-invasive approach for biological sex determination.”
The discriminative peaks are thought to reflect subtle differences in the enamel's molecular composition – likely related to residual peptide fragments from AMELX and AMELY isoforms embedded during enamel formation.
Traditional sex estimation methods, including osteometric analysis and DNA sequencing, are often limited by sample degradation, ethical concerns, or destructive requirements. Raman spectroscopy, by contrast, offers a rapid, portable, and non-invasive alternative. The technique could be particularly valuable when working with juvenile, fragmented, or culturally sensitive remains.
“Our method addresses a key challenge in the analysis of rare or valuable specimens,” the authors wrote, “offering a scalable approach that combines molecular sensitivity with sample preservation.”
Although this study focused on modern, well-preserved samples, the method holds promise for broader application in archaeological and forensic research – especially where sample integrity must be maintained.
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