The microbiome of Da Vinci’s drawings

Leonardo da Vinci’s work is a priceless 15th century heritage. From engineering to anatomy, the master paved the way for many scientific disciplines. But what could Da Vinci’s drawings teach us? Could molecular studies reveal interesting data from the past? These questions led an interdisciplinary team of researchers, curators and bioinformaticians, both from the University of Natural Resources and Life Sciences and the University of Applied Sciences in Vienna in Austria, as well as from the Central Institute of pathology of archives and books (ICPAL). in Italy, to collaborate and study the microbiome of seven different drawings by Leonardo da Vinci.

The molecular study of works of art has already proven to be a valuable approach and Dr. Piñar, the study’s first author, is not at his first attempt. In 2019, his team was able to investigate the storage conditions and even the possible geographical origin of three statues requisitioned from smugglers thanks to the study of their microbiome and, at the beginning of the year, the microbiome of ancient parchments allowed to elucidate the animal origin of the skins. used for their manufacture 1000 years ago. In the study presented here, the Austrian team uses an innovative genomic approach called Nanopore, considered third-generation sequencing, to reveal for the first time the complete microbiological makeup of several of Da Vinci’s drawings. The study is published today in Frontiers in microbiology.

Overall, the results show a surprising dominance of bacteria over fungi. Until now, fungi were considered a dominant community in the paper art and tended to be the primary focus of microbial analysis due to their potential for biodeterioration. Here, a high proportion of these bacteria are either typical of the human microbiome, certainly introduced by intensive manipulation of the drawings during restoration work, or correspond to insect microbiomes, which could have been introduced long ago by flies and their droppings. .

A second interesting observation is the presence of a large amount of human DNA. Unfortunately, we cannot assume that this DNA comes from the master himself, but rather it would have been introduced by conservators over the years. Finally, for bacterial and fungal communities, a correlation with the geographic location of the designs can be observed.

All in all, the insects, the restorers and the geographic location all seem to have left an invisible trace on the drawings. While it is difficult to say whether any of these contaminants originate from the time when Leonardo da Vinci was sketching his drawings, Dr Piñar underlines the importance that monitoring these data could have: “The sensitivity of the method of Nanopore sequencing offers an excellent tool for tracking art objects. It allows the evaluation of the microbiomes and the visualization of its variations due to harmful situations. This can be used as a bio-archive of the history of objects, providing a kind of fingerprint for current and future comparisons. “Thus, scientists could develop new methods to not only preserve the visual appearance of art, but also to document the invisible journey of our artistic and cultural heritage.