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Toxin gene determination and evolution in scorpaenoid fish
Po-Shun Chuang1, Jen-Chieh Shiao1
1Institute of Oceanography, National Taiwan University, Taipei, Taiwan.
Summary
Scorpionfish toxin genes were analyzed, revealing duplication before species diversification. This suggests these toxin genes are common across the Scorpaeniform family, with potential gene duplication in lionfish lineages.
Area of Science:
- Marine Biology
- Evolutionary Genetics
- Toxicology
Background:
- Scorpionfish (Scorpaenoidei) possess potent venom.
- Understanding the genetic basis and evolution of fish toxins is crucial.
Purpose of the Study:
- To determine toxin genes in four scorpaenoid fish species.
- To reconstruct the evolutionary history of these toxin genes.
- To investigate gene duplication events in scorpaenoid fish venom evolution.
Main Methods:
- cDNA and genomic DNA sequencing of four scorpaenoid fish species.
- Deduced protein sequence analysis.
- Phylogenetic analysis of toxin gene evolution.
- Intron position comparison across species.
Main Results:
- Toxin genes in Sebastapistes strongia, Scorpaenopsis oxycephala, and Sebastiscus marmoratus are approximately 700 amino acids.
- Highly conserved intron positions indicate the utility of genomic DNA for gene discovery.
- Phylogenetic analysis revealed toxin subunit duplication predates Scorpaenoidei speciation.
- Dendrochirus zebra possesses an additional toxin gene, suggesting a further duplication event before lionfish speciation.
Conclusions:
- Toxin genes likely originated before the diversification of Scorpaenoidei, suggesting they are common to the Scorpaeniform family.
- An additional gene duplication event occurred in the lineage leading to lionfish (Pteroinae).
- A pseudogene may be prevalent in the lionfish lineage, indicating ongoing evolutionary changes in toxin gene composition.
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