Blond hair color is more frequent in Europe than in any other part of the world. The estimated date of the genetic mutation that resulted in “blond” hair color was about 11,000 years ago during the last ice age. A typical explanation for the evolution of blond hair was the people of Northern Europe’s vitamin D absorption and synthesis. As Europeans were subjected to a seasonal deficiency of sunlight, which is required for vitamin D synthesis, they developed an adaptation for lighter skin. Light skin, which has a lower concentration of melanin pigmentation, allowed more sunlight to trigger the production of vitamin D. This light skin adaptation is thought to have caused the emergence of blond hair. Another valid hypothesis for the phenomenon was that blond hair evolved rapidly at a specific area at the end of the last ice age via sexual selection. The theory presents the possibility that the phenotypes of blond hair and blue eyes in some European women stood out from their adversaries in a time of competition for scarce males. According to the theory, this process of “sexual selection” spread to parts of Northern Europe, resulting in the modern predominance of light colored hair in those areas. Both the light skin adaptation and sexual selection hypotheses appear to be valid, but there is still debate over which one is actually responsible for the evolution of blond hair.
All info. used in writing this paper originated from the "Blond Hair" article on Wikipedia.