Characterization of Lophiotoma leucotropis Mitochondrial Genome of Family Turridae and Phylogenetic Considerations within the Neogastropoda.

Simple Summary: Lophiotoma leucotropis belongs to the Turridae and is a carnivorous snail that is widely distributed in shallow sea sand and intertidal zones around the world. Currently, the mitochondrial genome sequence of L. leucotropis has not been explored. And there is also great controversy over whether the order Neogastropoda to which L. leucotropis belongs is monophyletic. We sequenced the mitogenome of L. leucotropis and analyzed its basic gene characteristics. We found that it contains a total of 37 gene contents. Similar to species in the Turridae family, it has a higher content of AT bases and a preference for some codons. The selection pressure analysis results showed purification selection effects, and through comparison with other species in Turridae, it was found that the gene sequence of this species is conserved, which helps to deepen the understanding of the Turridae. We constructed a phylogenetic tree using the 13 protein coding genes of Neogastropoda and concluded that the order is monophyletic. This result is a supplement and validation to the research on the evolutionary status of Neogastropoda and also provides reference for the species classification and germplasm resource development of Neogastropoda. Neogastropoda is a group of marine organisms with an extremely wide distribution that is rich in species and economic and ornamental values, the classification of species in this order has been ongoing for a long time, but there is still a great controversy about whether this order is monophyletic. In this study, we obtained the complete mitogenome of Lophiotoma leucotropis by next-generation sequencing and analyzed the basic structural features of the genome, and we found that the number of genes was consistent with that of most of the Neogastropoda snails, containing 37 genes, including 13 protein-coding genes (PCGs), 2 rRNAs, and 22 tRNAs. Analyzing base content, amino acid content, codon usage preference, and tRNA structure, the mitogenomes of eight species of Turridae were selected for analysis of selection pressures, and it was found that the evolution of species in this family was affected by purifying selection. In addition, by analyzing the rearrangement characteristics, it was found that the sequence of L. leucotropis was consistent with the Conoidea consensus order, and four of the eight species involved in the analysis showed rearrangements. Finally, we constructed a phylogenetic tree by combining PCGs of 60 species within Caenogastropoda and found Neogastropoda to be a monophyletic group, validating the results of morphological classification. The results will provide more references for the classification and species evolution of Neogastropoda, as well as phylogenetic analysis. [ABSTRACT FROM AUTHOR]