Ancient Human DNA Discovered on Portugal Cave Walls

Researchers have identified ancient human DNA on cave walls in Portugal, marking the first time genetic material from prehistoric humans has been recovered directly from rock art surfaces, according to a study published in Nature. This discovery allows scientists to potentially link specific individuals to the creation of prehistoric art, providing a biological record of the artists themselves.

The findings indicate that human DNA can survive for millennia on cave walls. Previously, ancient DNA was primarily recovered from skeletal remains or sediment layers. The recovery of DNA from the art surfaces suggests that biological traces left by prehistoric humans—such as skin cells or saliva—can remain preserved in specific cave environments.

According to reporting from ZME Science, the discovery could rewrite the story of prehistoric art by shifting the focus from the images themselves to the biological identity of the people who painted them. By sequencing this DNA, researchers aim to determine the kinship and population movements of the artists.

The study focused on cave sites in Portugal, where the unique chemistry of the rock and the stable climate of the caves prevented the genetic material from degrading. This preservation allows for the use of high-sensitivity genomic sequencing to extract fragmented DNA strands from the wall surfaces.

How was ancient human DNA recovered from cave walls?

Scientists used specialized sampling techniques to collect material from the surfaces of the rock art without damaging the paintings. According to the Nature study, the researchers targeted areas where biological material was most likely to have adhered to the stone.

The process involved extracting environmental DNA (eDNA) and distinguishing it from modern contamination. This required strict laboratory protocols to ensure the DNA recovered belonged to ancient humans and not to the archaeologists or tourists who had visited the sites.

The DNA survived due to the specific mineral composition of the cave walls, which acted as a preservative. This differs from previous DNA recovery methods that relied on the protection offered by bone marrow or frozen permafrost.

Why does this discovery change the understanding of prehistoric art?

The ability to identify the artists biologically transforms rock art from a purely stylistic or symbolic study into a demographic one. According to Hyperallergic, this allows researchers to ask whether the art was created by a single family group or by diverse populations passing through the region.

This discovery creates a direct link between the artist and the artwork. While archaeologists have long speculated about the social structures of prehistoric humans, the DNA provides a verifiable record of who was physically present at the wall during the painting process.

The research also allows for a comparison between the DNA found on the walls and the DNA found in nearby burial sites. If the genetic profiles match, researchers can confirm that the people buried in the region were the same individuals creating the art.

What are the implications for future archaeological research?

The success of the study suggests that other rock art sites may contain similar biological traces. Researchers can now apply these sampling methods to other caves to map the movement of prehistoric humans.

This method provides a non-invasive way to gather genetic data. Instead of relying on the discovery of intact skeletons, which are rare, scientists can use the walls of the caves themselves as a genetic archive.

Future research will likely focus on whether the DNA can reveal specific health data or dietary habits of the artists, further deepening the understanding of prehistoric life.