Transcriptome Analysis of Natural Albino Northern Snakehead (Channa argus var.) Provides Novel Insights into Color-Related Genes

The northern snakehead (Channa argus) is an important economic fish species that holds a significant position in Chinese aquaculture due to its high nutritional value, fast growth, and anti-hypoxia capacity. There is a natural albino-mutant (AM) C. argus strain. Albinism, a stable genetic trait characterized by loss of body pigmentation, provides a unique opportunity to study the molecular mechanisms of vertebrate coloration. This study investigates the molecular mechanisms underlying albinism in C. argus through skin transcriptomic analyses of wild type (WT) and AM individuals. Morphological and histological analysis revealed no significant phenotypic difference between WT and AM in early development, whereas adult AM exhibited a severe reduction in melanocytes. Through RNA sequencing of skin tissues from WT-adult, AM-adult, and AM-15dpf, a total of 10,891 differentially expressed genes (DEGs) were identified. Through DEG enrichment analyses, we identified a series of enriched pathways and genes related to albinism, including melanogenesis (i.e., tyr, tyrp1b, kitb, kitlga, pmela, pmelb, mitfa, and mitfb) and xanthophore formation (i.e., pax3a, pax3b, pax7a, and sox10). In conclusion, this study not only enriches the research on fish pigmentation, but also has potential significance for the aquaculture and breeding of C. argus.