A New Frontier in Genetic Archaeology
For the first time, researchers have successfully recovered ancient human DNA directly from cave walls in Spain and Portugal. Historically, scientists have relied exclusively on human remains, artifacts, or sediment to extract genetic material.
Sampling the Prehistoric Record
Led by the First Art project, the research team collected over 100 samples from 11 prehistoric sites, including the renowned Cave of Altamira. To establish a scientific baseline, the team sampled both areas adorned with rock art and adjacent, unpigmented surfaces.
The results confirmed the presence of ancient human DNA in five instances. Surprisingly, only one positive sample originated from a painted surface—found in Portugal’s Escoural Cave. The remaining four samples were retrieved from blank walls at Escoural and Spain’s Covarón Cave.
Preservation in Unlikely Places
Evolutionary geneticist Alba Bossoms Mesa of the Max Planck Institute for Evolutionary Anthropology noted that the team initially prioritized pigmented areas. However, they soon discovered that unpigmented surfaces often yielded better-preserved genetic material. Although DNA naturally degrades, chemical analysis of molecular shortening indicates these samples are at least 2,000 years old. Some reveal genetic markers consistent with European hunter-gatherers from as early as 16,000 years ago.
The Complexity of Cave Contamination
The presence of DNA does not automatically link individuals to the creation of cave art. In three of the five positive samples, human DNA appeared alongside animal DNA, suggesting that environmental factors like water runoff or animal movement may have transported the material.
However, two samples from Escoural Cave contained exclusively human DNA, suggesting direct interaction with the wall. As noted by rock art specialist Benjamin Smith of the University of Western Australia, who was not involved in the research, this DNA could have been deposited by someone touching, sneezing, or urinating near the wall long after the paintings were completed.
Unlocking the Identity of Ancient Artists
Despite current limitations, the study serves as a vital proof-of-concept. Hipólito Collado Giraldo, an archaeologist with the government of Extremadura, suggests the technique could eventually help researchers understand the role of women in ancient art, track the migration of artists, and provide evidence for the artistic capabilities of Neandertals.
Future research will focus on refining methods to isolate genetic material specifically within pigment layers. If successful, scientists could date the DNA to the same period as the art, potentially identifying the individuals responsible for some of humanity’s earliest cultural expressions.
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