A study led by Harvard University researchers has revealed that the evolution of our species has been influenced far more by natural selection than previously thought. The study identified 479 genetic variants that were strongly selected for survival, including variants linked to red hair and pale skin. The discovery was enabled by an unusually large collection of ancient genomes from nearly 16,000 individuals spanning the last 10,000 years in West Eurasia. The researchers also used a new computational method to track the rise and fall of gene variants over extended periods. While the study did not directly test these variants, it suggested that the variants may have spread due to the shift from a hunter diet to a farmer diet, with more plants and grains, and that Europeans' skin adapted to the more prevalent vitamin D.