Human Hair Melanins: What We Have Learned and Have Not Learned from Mouse Coat Color Pigmentation

The document discussed the biochemical processes involved in human hair pigmentation, focusing on the production of eumelanin and pheomelanin by melanocytes. It highlighted the roles of tyrosine, tyrosinase, and related proteins in eumelanogenesis, and the necessity of cysteine for pheomelanogenesis. While extensive research had been conducted on mouse coat color pigmentation, less was known about the effects of protein mutations on human hair pigmentation, except for MC1R polymorphisms linked to pheomelanogenesis. The document emphasized the importance of pH and cysteine levels in melanosomes for controlling melanogenesis and proposed a hypothesis to explain the diversity of human hair pigmentation based on these findings.