Understanding the genetic basis of tetrodotoxin (TTX) accumulation and resistance in animals could provide us significant insights into adaptive evolution in ecological communities. It has been reported that TTX resistance is possibly due to gene mutation in sodium channels. Eating sea snail Nassarius has caused serious people poisoning and death incident due to tetrodotoxin (TTX) accumulation in their body. Here we conducted transcriptome analysis for both toxic and non-toxic communities in two Nassarius species (Nassarius succinctus and Nassarius variciferus) to reveal their genetic patterns of TTX accumulation and resistance. For genetic expression, the cellular and metabolic process, and binding and catalytic activity accounted for the top classification categories for both species. The toxic communities generally produced more up-regulated genes than non-toxic communities. The mostly different expression genes among toxic and non-toxic communities mainly included heat shock protein 83-like, cytochrome c oxidase subunit, WAS protein family member 2, delta-aminolevulinic acid dehydratase, protein transport protein Sec24D isoform X2 and so on, some of which referred to detoxification. In mutation level, the sodium channel gene of N. succinctus had one amino acid “L” that is different from that of other animals. The transcriptome analysis of both toxic and nontoxic communities in two Nassarius species provided important genetic basis for adaptive evolution research of TTX accumulation and resistance.
Understanding the genetic basis in animals possessing toxin could provide us significant insights into the adaptive evolution in toxin resistance. The reason of toxin resistance may refer to the mutation in sodium channels or the toxin-binding proteins. Sea snail Nassarius can accumulate tetrodotoxin (TTX) in their body and has caused serious people poisoning and death incident. However, the genetic basis of Nassarius including genetic expression and mutation has not been researched yet. Here we investigated the genetic basis from two Nassarius species (Nassarius succinctus and Nassarius variciferus) for TTX resistance with transcriptome. The genetic express pattern for both species was clearly revealed. The cellular and metabolic process, and binding and catalytic activity accounted for the top classification categories. The toxic samples generally produced more up-regulated genes than non-toxic samples. Some genes which possibly produce TTX-binding proteins were flagged. One sodium channel gene was identified from N. succinctus where one mutation cite was found as being different from all other animals included. The genetic basis of Nassarius revealed in this study would contribute to the further TTX-resistance mechanism research.