A recent analysis on DNA taken from the wisdom tooth of a 7,000-year-old human found in Spain in 2006 has overturned the popular image of light-skinned European hunter-gatherers.
April Holloway | Ancient Origins
The study revealed that the individual had dark hair, the dark-skinned genes of an African, though scientists don’t know this exact skin tone, and blue-eyes, which were thought to have been brought to Europe by late-arriving farmers who invaded the continent more than 5,000 years ago.
The new study, published in the journal Nature and led by Inigo Olalde of Spain’s Institut de Biologia Evolutiva in Barcelona, involved the first ever analysis of a pre-agricultural European genome and has given scientists an unprecedented glimpse of modern humans in Europe before the rise of farming.
The skeletons of two Mesolithic men were discovered in 2006 in a cave system in the Cantabrian Mountains, near León in northwest Spain. The remains, which belonged to two men in their early 30s, had been extremely well preserved by the cool environment of the cave. The artefacts found at the site, including perforated reindeer teeth that were strung and hung from their clothing, as well as the age of the bones, indicated that the individuals were hunter-gatherers.
After several failed attempts, the team of scientists finally managed to reconstruct an entire genome from DNA found in the root of a wisdom tooth in the better preserved of the two skeletons, and what they found was surprising.
The first unexpected finding was the fact the individual had dark skin. “The biggest surprise was to discover that this individual possessed African versions of the genes that determine the light pigmentation of the current Europeans, which indicates that he had dark skin,” said Dr Carles Lalueza-Fox from the Institute of Evolutionary Biology in Barcelona. “You see a lot of reconstructions of these people hunting and gathering and they look like modern Europeans with light skin. You never see a reconstruction of a Mesolithic hunter-gatherer with dark skin”.
The second surprise was that the man had blue eyes. This was also unexpected because the mutation for blue eyes was thought to have arisen more recently. Dr Lalueza-Fox said “Even more surprising was to find that he possessed the genetic variations that produce blue eyes in current Europeans, resulting in a unique phenotype [physical type] in a genome that is otherwise clearly northern European.” This hunter-gatherer is now the oldest known individual in Europe found to have blue eyes.
Previous research published in 2008 found that the earliest mutations in the eye-colour genes that led to the evolution of blue eyes probably occurred about 10,000 years ago in individuals living in around the Black Sea. The current study indicates that everyone with blue eyes today can trace their ancestry back to the same family in which this mutation first arose – and that the gene had travelled across Europe before the shift from hunting to farming, which is known to have spread from the east to the west.
It is not clear why blue eyes spread among ancient Europeans. One theory is that the gene could have helped to prevent eye disorders due to low light levels found in European winters, or that the trait spread because it was deemed sexually attractive.
But the physical traits were not all that the researchers uncovered. They also found that the individual was lactose intolerant and that his immune system genes were similar to those of modern humans. Previously, it was thought that many immunity genes evolved in farmers, not hunter-gatherers – partly to cope with diseases that spread due to close contact with animals, and partly because farmers lived in large, stationary populations through which disease could spread more easily. The fact that hunter-gatherers already had such immunity genes suggests that they were exposed to diseases not spread by animals, such as cholera.
THIS ARTICLE ORIGINALLY APPEARED AT Ancient Origins