Decay of Skin-Specific Gene Modules in Pangolins

This study investigates the genetic basis for skin adaptations in pangolins, which are known for their unique keratin-derived scales. By analyzing four pangolin genomes, the researchers found that genes related to sebum production, such as Awat1/2 and Dgat2l6, show patterns of inactivation, suggesting a decay of the pilosebaceous unit in these animals. However, the gene Elovl3, important for skin barrier function, remains intact and active. Additionally, genes involved in skin pathogen defense and keratinocyte layer integrity also exhibit inactivating mutations, indicating a complex evolutionary history of gene retention and loss in mammalian skin development. Contrary to what might be expected from the absence of sweat glands in pangolins, the gene Abcc11 is not inactivated, which differs from the pattern seen in cetaceans. This research highlights the intricate genetic changes that underlie the evolution of specialized skin features in mammals.