A new study led by researchers from Harvard University reveals that natural selection has played a much larger role in shaping our DNA than previously understood. The research highlights specific gene variants related to red hair and pale skin that have been favoured for survival. These findings provide a fresh perspective on human evolution over the last several thousand years.
Traditionally, scientists believed that human genetic evolution had slowed since the transition from hunting to farming. Earlier studies identified only 21 gene locations influenced by natural selection among Europeans over the past 10,000 years. However, the recent research discovered nearly 500 genetic variants that have been strongly selected, revealing a much more active evolutionary process.
The large-scale study analysed the DNA from around 16,000 ancient individuals, revealing changes in gene variants over time. Researchers employed a new computational method to pinpoint genes affected by natural selection, distinguishing them from those influenced by migration or chance.
Though the study does not directly address the reasons for the selection of these variants, one hypothesis suggests that variants of the MC1R gene, associated with red hair and pale skin, became advantageous for absorbing vitamin D from sunlight, especially as diets shifted towards agriculture.
The research underscores the complexities of tracking genetic adaptation. While some variants have declined over time, others have shown resilience. The researchers urge caution in interpreting these traits, as modern and ancient lifestyles differ greatly.
Ultimately, they aim to apply their methods globally, which could improve our understanding of disease risk and further illuminate human evolution.
