抄録
Hair color variation in primates, including humans, has evolved through complex genetic mechanisms influenced by thermoregulation, immune function, and social communication. Melanism, characterized by increased dark pigmentation, has independently arisen multiple times across primate lineages. However, the genetic underpinnings of melanism remain incompletely understood. In this study, we investigated the molecular basis of melanism by analyzing hair root transcriptomes from Macaca nigra, which exhibits uniform dark pigmentation, and Macaca ochreata, which displays a dark-light hair pattern. Principal Component Analysis of RNA-seq sequence revealed a strong correlation between PC1 and hair lightness (L), suggesting that genes contributing to PC1 were associated with darker pigmentation. Differential gene expression analysis identified key regulators of melanin synthesis and intracellular transport, including TYRP1, RAB27B, and DYNLT3. DYNLT3, a dynein-associated motor protein facilitating melanosome maturation and transfer to keratinocytes, was significantly upregulated in dark hairs of M. nigra. Additionally, RAB27B, a GTPase involved in endosomal trafficking, exhibited high expression, suggesting a potential role in intracellular vesicle transport contributing to pigmentation regulation in primates.These findings highlight the critical role of intracellular transport in primate melanism and provide a transcriptomic framework for understanding the genetic basis of pigmentation.
