Biological signatures of history: Examination of composite biomes and Y chromosome analysis from da Vinci-associated cultural artifacts

Abstract

Cultural heritage objects can accumulate DNA from materials, environments, and repeated human contact, but biomolecular profiling of such items is constrained by nondestructive sampling requirements, ultra-low biomass, and high contamination risk. Here we present a minimally invasive workflow that integrates gentle swab collection, low- input whole-metagenome sequencing, taxonomic profiling, and Y-chromosome analyses to recover "biological signatures of history" from Renaissance-era artwork and archival correspondence associated with ancestors of Leonardo da Vinci. Across artifacts, we recovered heterogeneous mixtures of microbial and eukaryotic DNA (including bacteria, fungi, plants, and viruses) consistent with composite "biomes" that reflect differences in substrate, storage, conservation treatments, and handling. Multivariate comparisons show reproducible sample-to-sample separations. In parallel, we assessed human Y-chromosome signal using a panel of [~]90,000 phylogenetically informative markers and partial Y-STR profiling where feasible. Across multiple independent swabs from Leonardo da Vinci-associated items, the obtained Y chromosome marker data suggested assignments withing the broader E1b1/E1b1b clade. However, the control samples also indicate mixed contributions consistent with modern handling and other sources. Together, these data demonstrate the feasibility as well as limitations of combining metagenomics and human DNA marker analysis for cultural heritage science, providing a baseline workflow for future conservation science studies and hypothesis-driven investigations of provenance, authentication and handling history.