Proteomic and metagenomic insights into prehistoric Spanish Levantine Rock Art

TL;DR

This study combines proteomic and metagenomic analyses to uncover the composition and potential preservation mechanisms of prehistoric Spanish Levantine rock art, providing new insights into its dating and cultural context.

Contribution

It is the first application of omic techniques to Levantine rock art, revealing bacterial communities and organic binders involved in the paintings.

Findings

Bacterial communities are dominated by Firmicutes species.

Proteomic analysis identified organic binders in the pigments.

The bacterial colonization may have a protective effect on the rock art.

Abstract

The Iberian Mediterranean Basin is home to one of the largest groups of prehistoric rock art sites in Europe. Despite the cultural relevance of prehistoric Spanish Levantine rock art, pigment composition remains partially unknown, and the nature of the binders used for painting has yet to be disclosed. In this work, we present the first omic analysis applied to one of the flagship Levantine rock art sites: the Valltorta ravine (Castell{\'o}n, Spain). We used high-throughput sequencing to provide the first description of the bacterial communities colonizing the rock art patina, which proved to be dominated by Firmicutes species and might have a protective effect on the paintings. Proteomic analysis was also performed on rock art microsamples in order to determine the organic binders present in Levantine prehistoric rock art pigments. This information could shed light on the controversial dating of this UNESCO Cultural Heritage, and contribute to defining the chrono-cultural framework of the societies responsible for these paintings.