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 two types of melanin: eumelanin and pheomelanin. It highlighted the role of tyrosine, tyrosinase, and related proteins in eumelanogenesis, and the additional requirement of cysteine for pheomelanogenesis. The study noted that while mouse coat color pigmentation has been extensively studied, there was limited understanding of the effects of mutations in these proteins on human hair pigmentation, except for MC1R polymorphisms associated with pheomelanogenesis. The authors emphasized the importance of pH and cysteine levels in melanosomes in controlling melanogenesis and proposed a hypothesis to explain the diversity of human hair pigmentation based on these factors.