Gene expression varies with disease and parasitism in the green sea turtle (Chelonia mydas) skin transcriptome

Primary author: Rachael Kane
Faculty sponsor: Andrew Storfer

Primary college/unit: Arts and Sciences
Campus: Pullman


Emerging infectious diseases (EIDs) are a major threat to biodiversity in the 21st Century. Fibropapillomatosis (FP) has been classified as an EID and it plagues both juvenile and adult marine turtles. FP is an epithelial tumor disease that affects marine turtles globally. While FP tumor gene expression has been characterized, no transcriptomics studies have been performed on healthy Chelonia mydas individuals or tissues. Here, we perform RNA-Seq on healthy skin tissue of juvenile C. mydas individuals with FP and without FP from the Indian River Lagoon, Florida, USA. We assembled a de novo C. mydas transcriptome to identify significantly differentially expressed genes (DEGs) based on turtle presence of FP tumors and leech parasitism. Significantly DEGs were found in all expression analyses and included candidate genes that may play a role in C. mydas recovery from FP. Although tumor inhibition genes were found to be expressed in both FP-negative and positive individuals, positive individuals had twice as many upregulated significantly differentially expressed genes, indicating a possible response to FP affliction. A general trend of downregulated intra- and inter- cell signaling genes was observed in the leech infected individuals. A Gene Ontology enrichment analysis showed few enriched biological processes. Interestingly, FP-negative individuals showed enrichment of T cell cytokine production. Clearly, C. mydas respond to disease and parasitism by regulating their transcription, and transcriptomics provides a promising venue to further explore this crippling disease.