A typical explanation found in the scientific literature for the evolution of light hair is related to the evolution of light skin, and in turn the requirement for vitamin D synthesis and northern Europe's seasonal less solar radiation.
Lighter skin is due to a low concentration in pigmentation, thus allowing more sunlight to trigger the production of vitamin D.
Recent archaeological and genetic study published in 2014 found that seven "Scandinavian hunter-gatherers" found in the 7,700-year-old Motala archaeological site in southern Sweden had both light skin gene variants, SLC24A5 and SLC45A2, and that they had a third gene, HERC2/OCA2, which causes blue eyes and also contributes to lighter skin and blond hair.
Genetic research published in 20 also indicates that Yamnaya Proto-Indo-Europeans who migrated to Europe in the Bronze Age were overwhelmingly dark-eyed (brown), dark-haired and had a skin colour that was moderately light, though somewhat darker than that of the average modern European.
The masculine version is used in the plural, in "blonds of the European race", Another hair color word of French origin, brunet(te) (from the same Germanic root that gave "brown"), functions in the same way in orthodox English.
The OED gives "brunet" as meaning "dark-complexioned" or a "dark-complexioned person", citing a comparative usage of brunet and blond to Thomas Henry Huxley in saying, "The present contrast of blonds and brunets existed among them." "Blond" and "blonde" are also occasionally used to refer to objects that have a color reminiscent of fair hair.
The resultant visible hue depends on various factors, but always has some sort of yellowish color.In western Europe during the Middle Ages, long, blond hair was idealized as the paragon of female beauty.The Norse goddess Sif and the medieval heroine Iseult were both significantly portrayed as blond and, in medieval artwork, Eve, Mary Magdalene, and the Virgin Mary are often shown with blond hair.The word was reintroduced into English in the 17th century from French, and was for some time considered French; in French, "blonde" is a feminine adjective; it describes a woman with blonde hair."Blond", with its continued gender-varied usage, is one of few adjectives in written English to retain separate masculine and feminine grammatical genders.