Sampling techniques and genomic analysis of biological material from artworks

The genomic analysis of biological material from artworks can be used to guide curation, preservation, and restoration. Additionally, human DNA recovered from artworks may provide other insights. However, the recovery of biological samples from artworks is dependent on the sampling technique used and the media from which the biological materials are recovered. The ideal sampling method should be noninvasive, yet robust. We studied five artworks on paper and compared three sampling methods, each with increasing degrees of invasiveness. Minimally invasive swabbing techniques collect samples from the surface, whereas more aggressive techniques such as wet vacuuming were expected to yield more biological material from within the support media and more likely to produce authentic DNA from the artwork. We report a comparison of collection techniques to generate microbial DNA sequence data, the conserved human gene RNase P, and Y-STRs from artworks on paper. We observed that wet vacuuming resulted in higher DNA recovery than double swabbing and core punches. Diverse microbial populations existed on the corners and centers of the five artworks studied, but the distribution of the total biomass was relatively even across the surfaces of the works sampled. Studies of peripheral regions, where sampling is less likely to cause alterations to the artwork, could thus yield useful results in microbiome and human DNA studies. These results provide a framework for sampling artworks on paper to obtain biological material. The methods described may provide microbiome identification to facilitate restoration and preservation, and might also contribute to the determination of provenance.