| Summary: | 碩士 === 國立臺灣大學 === 海洋研究所 === 102 === More than 1200 fish species among acanthomorpha might be venomous. Scorpaenoidei, a diverse suborder of ray-finned fish, is a hotspot of venomous fish and possesses a large pool of potential bioactive molecules. In the present study we determined the venom genes from three scorpaenoid fishes and reconstructed their evolutionary relationship. The deduced amino acid sequences of two venom subunits in Sebastapistes strongia, Scorpaenopsis oxycephala, and Sebastiscus marmoratus are about 700 a.a. (698~703 a.a.), corresponding to the size of stonefish and lionfish venoms. Phylogenetic analysis shows that the two gene subunits were duplicated prior to the speciation of Scorpaenoidei and may be common to the whole Scorpaeniform family. In addition, another gene duplication event occurred before the speciation of lionfish (Pteroinae), thus generating the two venom subunits in the genus Pterois. The venom genes determined from the genomic DNA of Dendrochirus zebra show three types of venom genes in the genome, implying that a pseudogene may present in Pteroinae. The expression pattern of the venom genes in different tissues of Se. marmoratus were evaluated by RT-qPCR, respectively. The dorsal spines were found to be the most venomous part of the fish, while lesser amounts of the venom genes were detected in other fins. The venom expression pattern seems to reflect the defensive purpose of the venom, with the most easily attacked part expressing the highest venom levels.
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