A large-scale genetic study suggests that the gene associated with red hair has increased in frequency in Europe over the past 10,000 years, likely as a result of natural selection and changing environmental pressures.
Researchers analyzing ancient and modern DNA have identified widespread evolutionary shifts in human traits, including those linked to pigmentation, immunity, and metabolism.
Ancient DNA reveals evolutionary changes
The study examined genetic material from nearly 16,000 ancient human remains and more than 6,000 modern individuals, making it one of the most extensive analyses of human evolution to date.
Scientists identified 479 genetic variants that became more common over time, including those associated with red hair and lighter skin pigmentation. These traits are believed to have played a role in how humans adapted to different environments across Europe.
Previous research suggests that individuals with lighter skin and red hair may produce vitamin D more efficiently, potentially offering an advantage in regions with lower sunlight exposure.
Evolution continued after farming began
The findings support the idea that human evolution did not stop with the transition to agriculture. Instead, natural selection continued to shape hundreds of genes linked to health and physiology.
Some genetic changes, however, remain difficult to explain. One variant associated with a higher risk of celiac disease appeared around 4,000 years ago and still became more common over time, suggesting it may once have provided survival or reproductive benefits.
Similarly, a variant of the immune-related gene TYK2, which increases susceptibility to tuberculosis, rose in frequency between 9,000 and 3,000 years ago before later declining. Researchers believe such changes may reflect shifting advantages in response to infectious diseases prevalent at different times.
Diet, farming, and survival traits
The study also found a decline in genetic variants linked to increased fat storage. Researchers suggest this may relate to the so-called “thrifty gene” hypothesis, which proposes that energy-storing traits were beneficial for hunter-gatherers but became less advantageous once farming provided more stable food supplies.
As agriculture spread, stable access to food may have reduced the survival benefit of genes that promoted high fat storage.
Complex patterns in human genetics
Scientists caution that the results mainly reflect populations in Western Eurasia, and it remains unclear whether similar evolutionary patterns occurred in other regions of the world.
Still, the findings highlight the complex and ongoing nature of human evolution, showing how traits such as hair color, immunity, and metabolism have been shaped by shifting environments, diets, and diseases over thousands of years.
