The commonly accepted theory of skin color evolution holds that early humans developed lighter skin as they moved away from Africa and into Europe’s northern latitudes. The idea was that lighter skin allowed for more efficient production of vitamin D in low-light environments. However, research into ancient European DNA, analyzing samples from over 300 individuals, reveals that the majority of early Europeans had dark skin—much darker than modern Europeans—until relatively recently in history.
The study, published in PNAS, was led by Guido Barbujani at the University of Ferrara and builds on previous research showing how genetic adaptations unfolded over time. By examining genomes from 348 individuals who lived between 45,000 and 1,700 years ago, researchers have challenged the traditional narrative, providing new insights into the complex history of human pigmentation.
The Slow Transition to Lighter Skin
Most of Europe’s inhabitants maintained dark or intermediate skin tones long after modern humans first arrived on the continent. In fact, genetic analyses reveal that as late as 3,000 years ago, half of the people in Europe still had dark skin.
It wasn’t until the Bronze and Iron Ages, around 3,000 years ago, that lighter skin tones began to emerge as a dominant trait in the population. According to the study, early evidence of light skin appears as early as the Mesolithic period, but even then, it was still relatively rare.
Interestingly, the shift to lighter skin was not a quick or uniform process. Researchers found that the first clear genetic markers for lighter skin came with the spread of Neolithic farmers from Anatolia around 10,000 years ago, reports ZME Science.
These early agriculturalists carried genes that likely made them more suited to Europe’s low sunlight. However, it took thousands of years for these genes to spread widely across Europe, a transition that was gradual and varied by region.
Dark Skin and the Role of Vitamin D
The study also sheds light on the role of vitamin D in the evolution of human skin color. While the classic explanation for the development of lighter skin holds that it helped ancient Europeans produce more vitamin D in less sunny environments, the researchers argue that dietary changes might have also played a significant role.
Early agricultural societies, with their reliance on crops rather than wild game, had lower levels of vitamin D in their diets. In regions where people shifted to farming, the need to absorb more sunlight for vitamin D could have driven the genetic change toward lighter skin.
What’s especially significant is that researchers have identified the key genetic variants that contributed to this shift. Variants in the TYR and SLC24A5 genes, which are strongly associated with lighter skin, were absent in early European populations. However, these variants became more prevalent over time, culminating in the lighter skin seen in later populations, such as a Bronze Age individual from Hungary, who had blue eyes and blonde hair.
The Legacy of Neanderthals and the Genetic Puzzle
Despite the centuries of interaction between Neanderthals and early humans, the study found no evidence to support the idea that lighter skin in modern Europeans came from their Neanderthal ancestors.
While the two groups interbred, it appears that the genetic variants responsible for lighter skin evolved independently in modern humans. This finding underscores the complex genetic landscape of early Europe and the multiple factors that influenced the evolution of human traits like skin color.
These new insights have been made possible by advances in ancient DNA sequencing technology, which allow researchers to extract genetic information from fragmented and degraded samples. This is a major leap forward in understanding human prehistory, as it gives us a clearer picture of how migration, climate, diet, and genetics all intertwined to shape the populations of ancient Europe.