This study analyzed genome-wide data from over 500,000 UK Biobank participants to identify genetic variants associated with hair color. It found that 15 variants in the MC1R gene explained 93% of heritability for red hair. 64 variants explained 73% of heritability for blonde hair and 56 variants explained 47% of heritability for brown hair. It also discovered epistatic interactions between MC1R and other loci influencing hair color. However, results may only apply to white British individuals as hair color was self-reported.