Color morphs in Apostichopus japonicus: Physiology and molecular regulation mechanisms

Body color and coloration patterns are important phenotypic traits associated with survival and reproductive activities—including camouflage, thermoregulation, mating selection, social interaction, desiccation resistance, salinity adaptation, and immunity—in many organisms. Considering those functions, some species may show rare and beautiful coloration. Here, we explore the physiological, environmental adaptation, and genetic differences of different color morphs of the sea cucumber Apostichopus japonicus and discuss the pigmentation regulation mechanism underlying color morph formation using new technologies including genomics. Transcriptomics and proteomics were used to identify important genes and proteins that are involved in the mechanisms of pigmentation, body color polymorphism, and albinism in A. japonicus. Chromatin accessibility signatures have been identified using ATAC-seq. These findings will further our understanding of how echinoderm body color is controlled and create the groundwork for the breeding of variants of A. japonicus with unique body colors.