For decades, scientists assumed that the first modern humans to reach Europe, about 45,000 years ago, quickly evolved pale skin to adapt to the faint sunlight of the region. Logic seemed simple: lighter skin allows more ultraviolet light to penetrate, helping the body to produce vitamin D, an essential nutrient for human health.
However, a new study of the challenges of ancient DNA this long data assumption. When analyzing the genomes of 348 individuals who lived between 45,000 and 1,700 years, researchers have discovered a surprising truth: for most of the history of Europe, most of its inhabitants had dark skin. About 3,000 years ago, the lighter skin tones became dominant.
Dark skin Europe
The color of the skin is one of the most visible features of humans, but their evolution has been wrapped in mystery. The first humans in Africa probably had dark skin, which protected them from the intense ultraviolet radiation (UV) of Ecuador. As humans emigrated north to Europe and Asia through Levante, where UV ray levels were lower, the lighter skin became advantageous. This allowed a more efficient production of vitamin D, which is important for bone health.
But the new study reveals that this transition was anything but simple. Even at the ages of copper and iron, around 5,000 to 3,000 years ago, half of the individuals analyzed still had dark or intermediate skin tones.
A 2023 study found that Ötzi, the famous mummy of ancient glacier who lived 5,300 years before succumbing to a violent death in the Alps, was dark skinned. The color of his skin was genetically determined to be darker than the modern ones in southern Europe, but clearer than the modern sub -Saharan Africans.
“It is the darkest skin tone that has been registered in contemporary European individuals,” explained anthropologist Albert Zink, co -author of the study and head of the EURAC Research Institute for Mumas studies in Bolzano at the time the study of Ötzi DNA.
Previously, in 2018, when scientists sequenced the DNA extracted from the oldest complete skeleton in Great Britain, a 10,000 -year -old man known as the Cheddar man, they were stunned to discover that man had dark brown skin and blue eyes.
During much of the tens of thousands of years covered by the DNA sampled in the new study led by Guido Barbujani at the University of Ferrara in Italy, 63% of the old Europeans had dark skin, while only 8% had skin pale The remaining individuals fell into some intermediate point. These findings are based on DNA extracted from bones and teeth, combined with advanced forensic techniques that predict the color of the skin, eyes and hair of genetic markers.
The researchers used a sophisticated probabilistic method to estimate the pigmentation features of the old DNA, which is often fragmented and degraded. They tested their approach to two ancient genomes of high coverage: UST’ -ishim, a 45,000-year-old man from Siberia, and SF12, an individual of 9,000 years of Sweden. By sampling the data to simulate lower coverage, they discovered that their method could reliably predict the pigmentation features even with very limited genetic information.
A slow march to the clearest skin
The first signs of lighter pigmentation appeared in the Mesolithic, around 14,000 to 4,000 years, with some individuals in Sweden and France showing light skin and blue eyes. In the bronze age (7,000 to 3,000 years ago), the proportion of dark skin individuals had fallen to approximately half. It was not until the Iron Age (from 3,000 to 1,700 years ago) that the lighter skin tones began to dominate.
But the true turning point came with the propagation of Anatolia Neolithic farmers about 10,000 years ago. These first farmers carried genes for clearer skin, which probably gave them an evolutionary advantage in the least sunny climates in Europe. Over time, their genes spread, but the process was slow and unequal.
However, they also found that localized migration and mixing processes played an important role. In some regions, the dark skin persisted for thousands of years more than in others.
The study also discovered intriguing patterns in the color of the eyes and hair. Clear eyes reached frequency during the mesolithic, long before the lighter skin became common. While dark hair remained the norm during most of the prehistory, the first instances of blond and red hair appeared in the age of neolithic and bronze.
Why changed skin color?
The question remains: Why did the clearest skin become more common in Europe? The traditional explanation, which pale skin evolved to maximize the production of vitamin D in low -light environments, may not tell the whole story. Jablonski suggests that changes in the diet played a crucial role. Instead, changes in the diet may have played a key role.
As humans went from small and nomadic groups to larger agricultural communities, their diets changed. They trusted less in the wild game rich in vitamin D and more in cultivated crops, which lacked vitamin. This change, combined with the need to absorb more sunlight in northern latitudes, may have driven the evolution of the clearest skin.
Neolithic expansion and massive migration waves to the east of anatolia may have greatly contributed to the transition from Europe to pale skin through the mixture of populations.
What about the Neanderthals who occupied Europe for tens of thousands of years before modern humans would enter the scene? Interestingly, the study confirms that modern Europeans did not inherit the pale skin of the Neanderthals. Previous investigations have shown that the two groups intertwined, but genetic evidence suggests that clearer skin evolved independently in modern humans.
The study also sheds light on specific genes that played a key role in the evolution of pigmentation. For example, the researchers identified two variants in genes Tyr and SLC24A5 They are strongly associated with lighter skin. These variants were absent in the Ust’ -ishim Paleolithic man but present in an individual of the Bronze Age of Hungary, who had light skin, blue eyes and blond hair.
While DNA provides the most direct evidence of old skin color, researchers have also sought art in search of clues. Ancient Egyptian works of art, for example, often represent women with lighter skin than men. However, depending too much on artistic representations can be a trap.
In the end, the history of human skin color is not just about biology, but it is about the trips that our ancestors took, the environments to which they adapted and the genetic legacy they left behind. And thanks to the old DNA, we can now begin to unravel that story, a genome at the same time.
The results appeared on the predimpression server Biorxiv.
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