Abstract: In this study, specific primers were designed for molecular cloning from the genomic DNA of three cone snails from the South China Sea:Conus imperialis, Conus virgo, andConus marmoreus. The authors cloned the complete sequence of 8 A-superfamily conotoxin precursor genes, with 4 fromC. imperialis, 2 fromC. virgo, and 2 fromC. marmoreus. The authors analyzed the intron sequence characteristics and the relationship between molecular evolution and diet, conducted a systematic analysis of the sequence structural A-superfamily conotoxin gene structures, and constructed an intron-based phylogenetic tree. The intron lengths of the A-superfamily conotoxin genes ranged from 139 bp to 1010 bp, and the GT or TG dinucleotide simple repeat sequences (units) were all located at the intron ends, indicating possible insertions/deletions in the A-superfamily conotoxin intron region. This study represented the first complete cloning of A-superfamily conotoxin genes fromC. imperialis,C. virgo, andC. marmoreus. It indicated that the evolution of introns in the A-superfamily conotoxin precursor genes was influenced by diet, and elaborated on the structural features and the molecular evolutionary mechanisms of this superfamily gene. Additionally, intron conservation in conotoxin precursor genes of the same superfamily served as molecular markers for primer design, which discovered more new conopeptide amino acid sequences from different species and individuals ofConus. This research is expected to provide a plethora of new molecules for subsequent artificial synthesis and new drug development.

Key words: A-superfamily conotoxin, intron, simple sequence repeat, phylogenetic tree；Conus