Molecular phylogeny of the land snail genus Alopia (Gastropoda: Clausiliidae) reveals multiple inversions of chirality

Whereas the vast majority of gastropods possess dextral shell and body organization, members of the Clausiliidae family are almost exclusively sinistral. Within this group a unique feature of the alpine genus Alopia is the comparable representation of sinistral and dextral taxa, and the existence of enantiomorph taxon pairs that appear to differ only in their chirality. We carried out a molecular phylogenetic study, using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences, in order to find out whether chiral inversions are more frequent in this genus than in other genera of land snails. Our results revealed multiple independent inversions in the evolutionary history of Alopia and a close genetic relationship between members of the enantiomorph pairs. The inferred COI phylogeny also provided valuable clues for the taxonomic division and zoogeographical evaluation of Alopia species. The high number of inverse forms indicates unstable fixation of the coiling direction. This deficiency and the availability of enantiomorph pairs may make Alopia species attractive experimental models for genetic studies aimed at elucidating the molecular basis of chiral stability. © 2013 The Linnean Society of London