Scientists have made an exciting discovery that could change the way we study human history.
For the first time, researchers have shown that ancient human DNA can survive on cave walls for thousands of years.
This means that caves may hold hidden clues about the people who visited them long ago, even when no bones or other human remains are present.
The research was carried out by an international team of scientists from several countries, including Spain, Portugal, the United Kingdom, China, and Germany.
Their findings were published in the journal Nature Communications.
The study was part of the First Art project, which aims to learn more about the world’s oldest cave paintings. The researchers wanted to find out not only when the art was created, but also whether the artists themselves had left behind tiny traces of DNA.
To investigate, the team collected 54 samples from 11 caves in Spain and Portugal. These included painted and unpainted pieces of cave walls, ancient bones, cave sediments, and even a prehistoric bird bone tool that was once used like an airbrush to spray red paint onto cave walls.
Using advanced DNA extraction and sequencing technology, the scientists searched for ancient genetic material. They expected to find DNA in some of the painted areas, but they were surprised by what they discovered.
Only five samples contained genuine ancient human DNA. One came from a mineral crust covering a painted section of Escoural Cave in Portugal. The other four came from cave walls that showed no visible signs of artwork. Two of these were found near cave paintings in Covarón Cave in northern Spain.
In two of the samples, researchers found only human DNA and no animal DNA. This suggests that the DNA was probably left directly by people through saliva or other body fluids when they touched, spoke near, or blew pigment onto the cave walls. Other samples contained both human and animal DNA, suggesting that water or sediment may have moved the DNA onto the wall over time.
The scientists could not prove that the DNA belonged to the artists who created the cave paintings. However, they say this is the first clear evidence that human DNA can survive on cave walls for thousands of years.
Further analysis showed that most of the DNA came from females, while one sample mainly came from a male. The DNA from two samples belonged to modern humans who were part of the Western hunter-gatherer population that lived in ancient Europe.
Interestingly, the team found no ancient human DNA on the prehistoric airbrush tool from the famous Altamira Cave. Researchers believe this is because the tool has been handled by many people over the years, allowing modern DNA to contaminate it.
Although the discovery is exciting, ancient DNA was found in only a few locations. This shows that DNA does not survive well on every cave wall. Scientists now hope to improve their methods and study more caves around the world.
If successful, future research could reveal who visited these caves, whether they were men or women, where they came from, and perhaps even identify some of the people who created the world’s oldest cave art.
