Conclusion
This study revealed the genetic patterns of TTX accumulation and
resistance in two Nassarius species by transcriptome analysis.
For gene expression, the cellular and metabolic process and binding and
catalytic activity accounted for the top classification categories for
both N. succinctus and N. variciferus . The toxic specimens
showed more upregulated genes compared with the non-toxic specimens bothN. succinctus and N. variciferus . The heat shock protein
and cytochrome c oxidase subunit were found as the most significant
different expression genes between all the toxic and non-toxic groups,
which are mainly related with the metabolic mechanism of detoxification
and various diseases. Compared with other animals possessing toxin
resistance, one new amino acid āLā was found in the sodium channels ofN. variciferus , which could possibly be the mutation for blocking
the TTX-binding. Future studies should focus on exploring the complete
sodium channel genes of various Nassarius species and detailed
metabolic pathways for TTX resistance in Nassarius .