Comparative Transcriptomic Analysis of Left-Right Sensory Differences in Haliotis discus hannai

Asymmetric development, in which functional differences occur between left-right symmetrical organs, is widespread in organisms, including fish and mollusks. However, the asymmetry of symmetrical sensory structures in Haliotis discus hannai, a gastropod with a sensitive sensory system, remains unknown. This study analyzed the transcriptomes of three sensory structures (eyestalks, cephalic tentacles, and epipodial tentacles) to explore potential asymmetries in this species. RNA-seq revealed functional differences in sensory ability and sperm-egg recognition between right and left eyestalks, with cephalic tentacles displaying asymmetry in cytoskeletal organization and cell cycle regulation. Epipodial tentacles showed similar asymmetries, including immune response differences. Moreover, the cAMP-protein kinase A (PKA)-CREB-binding protein (CBP) signaling pathway responded asymmetrically, with PKA responding to activators and inhibitors on both sides and CBP showing a stronger response on the right. These findings provide insights into sensory asymmetry in mollusks and guidance for further investigations of the molecular mechanisms underlying asymmetry in symmetrical organs. Overall design: This study focuses on the left and right sensory organs (particularly the eyestalks and tentacles) of Haliotis discus hannai, utilizing transcriptome sequencing to analyze the differences in gene expression between the left and right sides. The experimental design includes the following steps: 1. Collecting tissue samples from the left and right eyestalks and tentacles of abalones. 2. Extracting total RNA and performing high-throughput sequencing to obtain 3. comprehensive gene expression profiles. 4. Comparing gene expression differences between left and right tissues to identify key differentially expressed genes. 5. Analyzing the expression patterns of genes related to the cAMP-PKA-CBP and TGF-ß signaling pathways in left and right tissues. 6. Validating the expression of key genes using qPCR to ensure data reliability. This study aims to uncover the molecular regulatory mechanisms underlying the asymmetry of abalone sensory organs and provide new insights into the evolution and adaptation of sensory functions in mollusks.