Mitochondrial genome of (Gastropoda: Lymnaeoidea): Implications for snail systematics and schistosome epidemiology.

Many freshwater snails of the genus act as intermediate hosts in the life-cycles of schistosomes in Africa and adjacent regions. Currently, 37 species of representing four groups are recognised. The mitochondrial cytochrome oxidase subunit 1 (1) gene has shown utility for identifying and differentiating species and groups, but taxonomic relationships based on genetic data are not entirely consistent with those inferred using morphological and biological features. To underpin future systematic studies of members of the genus, we characterised here the mitochondrial genome of (from a defined laboratory strain) using a combined second- and third-generation sequencing and informatics approach, enabling taxonomic comparisons with other planorbid snails for which mitochondrial (mt) genomes were available. Analyses showed consistency in gene order and length among mitochondrial genomes of representative planorbid snails, with the lowest and highest nucleotide diversities being in the cytochrome oxidase and nicotinamide dehydrogenase subunit genes, respectively. This first mt genome for a representative of the genus should provide a useful resource for future investigations of the systematics, population genetics, epidemiology and/or ecology of and related snails. The sequencing and informatic workflow employed here should find broad applicability to a range of other snail intermediate hosts of parasitic trematodes.