Comparative Transcriptome Analysis of Toxic and Non-Toxic Nassarius Communities and Identification of Genes Involved in TTX-Adaptation.

Nassarius has caused serious people poisoning and death incident as a popular food due to tetrodotoxin (TTX) accumulation in their body. Understanding the genetic basis of tetrodotoxin (TTX) transformation and resistance in animals could lead to significant insights into adaptive evolution to toxins and toxin poisoning cures in medicine. Here we performed comparative transcriptome analysis for toxic and non-toxic communities in Nassarius succinctus and Nassarius variciferus to reveal their genetic expression and mutation patterns. For both species, the cellular and metabolic process, and binding and catalytic activity accounted for the top classification categories, and the toxic communities generally produced more up-regulated genes than non-toxic communities. Most unigenes and different expression genes were related to disease, e.g., heat shock protein and tissue factor pathway inhibitors, which involve detoxification and coagulation. In mutation levels, the sodium channel gene of N. succinctus had one amino acid mutation "L", which is different from that of other animals. In conclusion, the comparative transcriptome analysis of different species and populations provided an important genetic basis for adaptive evolution to toxins, health and toxin poisoning cure research for TTX in marine gastropoda mollusk. Future studies will focus on the action mechanism of the important functional gene for TTX accumulation and resistance.