New DNA tests reveal hidden biological traces on Renaissance art

By Vijay Kumar MalesuReviewed by Lauren HardakerJan 8 2026

A new preprint reveals how swabbing priceless artworks uncovers centuries of biological history, while showing why genetic clues to famous artists remain intriguing but inconclusive.

Study: Biological signatures of history: Examination of composite biomes and Y chromosome analysis from da Vinci-associated cultural artifacts. Image credit: Corona Borealis Studio/Shutterstock.com 

*Important notice: bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

In a recent pre-print study posted to the bioRxiv server, researchers evaluated whether minimally invasive deoxyribonucleic acid (DNA) sampling can recover meaningful biological and paternal lineage signals from Renaissance-era cultural artifacts.

How centuries of handling leave biological traces

Cultural heritage objects are handled, stored, conserved, and transported through generations, allowing biological material from many different individuals across centuries to build up on their surfaces. Advances in next-generation sequencing (NGS) now allow researchers to analyze these microscopic residues without harming irreplaceable artifacts. Such analyses may help conservators track biodeterioration and explore historical context.

However, surface-derived DNA is very limited, fragmented, and vulnerable to modern contamination, making interpretation difficult. Figuring out which signals are authentic versus incidental remains a key challenge. More research is needed to improve contamination-aware methods for historical inference.

Swabbing Renaissance artworks without damaging them

The study sampled cultural artifacts, including a Renaissance drawing attributed to Leonardo da Vinci called The Holy Child, archival letters from his ancestor Frosino di Ser Giovanni da Vinci, and comparison artworks by Filippino Lippi, Andrea Sacchi, and Charles Joseph Flipart, using minimally invasive double-swab techniques.

Depending on conservation limits, either wet-dry or dry-dry swabbing was used to collect biological material from the surfaces. Buccal swabs from contemporary male and female volunteers, as well as environmental swabs, served as controls.

DNA extraction took place in a polymerase chain reaction (PCR) clean room using a magnetic bead-based forensic kit. The DNA was quantified using spectrophotometric and fluorometric methods.

Researchers prepared whole-metagenome sequencing libraries directly from the recovered DNA without host DNA depletion and sequenced them on an Illumina NovaSeq X Plus platform (2 × 150 bp). The reads were assembled, filtered, and classified using standardized bioinformatics processes designed for ultra-low-input material.

For human genetic analysis, sequencing reads were matched to a complete human reference genome that includes the Y chromosome. Phylogenetically informative Y-chromosome markers were examined to assess the feasibility of paternal lineage. Partial Y-chromosome short tandem repeat (Y-STR) profiling was performed on selected samples to support lineage inference, while considering mixed contributions.

Low DNA yields but rich biological signatures

The DNA yields from all the sampled artifacts were low, reflecting the expected challenges of surface-derived material.

Nevertheless, sequencing revealed a diverse range of biological signatures, including bacteria, fungi, plants, animals, and viruses. Bacterial DNA made up the majority of the classified reads, with common skin-associated taxa like Cutibacterium acnes, highlighting the significant influence of human handling.

Fungal taxa included organisms frequently found on paper and wooden materials, some of which are known to contribute to biodeterioration, reinforcing the value of these analyses for conservation monitoring. Plant DNA assignments varied across the objects and included species matching environmental dust, paper production, and conservation materials. While some species may connect to Renaissance-era European contexts, these findings were interpreted with caution since plant DNA can come from many non-historical sources.

Viral sequences mainly consisted of bacteriophages and human-associated viruses, again pointing to modern contact as a key factor.

Notably, low-level assignments to pathogens, such as Plasmodium species, were detected in one archival letter; however, the authors stressed that such findings require targeted validation and should be interpreted with particular caution, given the instability of taxonomic classification in low-biomass metagenomic datasets.

Multivariate analyses of combined microbial and eukaryotic profiles revealed consistent differences between artifacts, suggesting that each object has a distinct composite “biome.”

These differences likely stem from variations in substrate, storage history, conservation treatment, and handling, rather than unique historical events.

Control samples highlighted how easily low-biomass surface DNA can be influenced by modern contamination and analytical choices, thereby limiting the strength of object-specific historical inference and emphasizing the need for careful, contamination-aware interpretation.

Human DNA was detectable at low levels in several samples, allowing for exploratory analysis of male-specific genetic markers. Y-chromosome reads were scarce, but a subset of artifacts linked to Leonardo consistently supported assignments within the broader E1b1 and E1b1b haplogroups. These lineages are common in Mediterranean populations, including parts of Italy, making them historically plausible but not conclusive proof of authorship.

Control samples also carried related haplogroups, indicating mixed contributions from modern handlers and reinforcing that surface DNA reflects cumulative contact rather than a single historical individual.

Partial Y-STR profiling demonstrated feasibility, with several artifacts yielding incomplete yet interpretable profiles. Bayesian haplogroup estimation based on Y-STR values showed a high posterior probability for E1b1b in the Holy Child drawing, while the archival letters showed split support between E1b1b and I1.

One comparator artwork by Andrea Sacchi also exhibited a high probability for E1b1b. These patterns complicate efforts to uniquely associate the signal with Leonardo himself, particularly because Bayesian Y-STR assignment becomes less reliable as locus coverage decreases. Multiple alleles at some loci confirmed that surface-derived DNA represents mixtures rather than single individuals.

Overall, the results highlight both the potential and the strict limitations of extracting historical genetic insights from cultural heritage objects.

A cautious path forward for art genomics

Minimally invasive DNA sampling combined with low-input metagenomic sequencing can recover rich, multi-domain biological profiles from Renaissance-era cultural artifacts. These profiles are best viewed as composite records shaped by materials, environments, conservation history, and human contact over time.

While preliminary Y-chromosome analyses suggest potential for detecting shared paternal lineage signals, heterogeneous Bayesian assignments, limited coverage, and contamination hinder definitive historical attribution. For conservators, this method offers practical tools for monitoring artifact condition and handling history. For historians, it emphasizes the need for caution when interpreting molecular data derived from object surfaces rather than biological remains.

Future studies should integrate additional artifacts, replicate findings, and include complementary molecular methods to draw stronger conclusions.

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*Important notice: bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.