Forensic Sci Int. 2025 Nov 7;378:112710. doi: 10.1016/j.forsciint.2025.112710. Online ahead of print.
ABSTRACT
Friction ridge skin patterns, including latent fingerprints (LFs), have long been essential for human identification. However, traditional ridge examinations do not convey temporal information. The ability to estimate the Time-since-Deposition (TsDp) of LFs could provide valuable chronological context in criminal investigations, helping to reconstruct timelines and corroborate alibis. A recent study explored LF microbiota as potential biological “clocks” for TsDp estimations at the Phylum taxonomical rank. In that instance, it was revealed that the composition, relative abundance, and succession patterns of microorganisms varied over time. This dynamic nature made the transferred skin microbiome a promising candidate for investigating predictable temporal changes of LFs in semi-controlled environments, such as indoor locations. The present article further expands the taxonomic resolution of the original study by identifying time-dependent microbial taxa at the Family rank and suggesting specific temporal signatures through statistical analyses. The same experimental conditions were considered: three donors, hand washing conditions, and aging for 1, 7, 14, and 21 days. For this analysis, the relative abundance, presence, and temporal shifts were examined with a focus on time-variant taxa. The 16S rRNA gene (V4 region) sequencing revealed distinct temporal signatures across the observed time points and handwashing conditions. For example, in unwashed hands, the combined presence of Mycosphaerellaceae and Coxiellaceae indicated a freshly deposited LF. In contrast, under washed conditions, the presence of Ruminococcaceae and Beijerinckiaceae was associated with a recent deposition. These preliminary findings further demonstrate the potential of microbiome analysis as a forensic tool for estimating TsDp in LFs and are a feasibility study for further work.
PMID:41213205 | DOI:10.1016/j.forsciint.2025.112710
