Population structure and genetic diversity in the invasive freshwater snail Galba schirazensis (Lymnaeidae)

We studied the population genetic structure of the freshwater snail Galba schirazensis (Kuster, 1862), a potential vector of infectious diseases such as fascioliasis. Galba schirazensis has now a worldwide distribution but a poorly known origin because this species has been distinguished only recently from the morphologically similar and cosmopolitan Galba truncatula. We developed specific microsatellite markers and sequenced a mitochondrial gene (cytochrome oxidase subunit I) to study individuals of G. schirazensis from the Old World and New World. We found very low genetic diversity within populations, no heterozygotes, and marked population structure—a pattern observed in other highly selfing lymnaeid species with recently enlarged distributions as a result of biological invasions. The total lack of observed heterozygosity in the few populations of G. schirazensis that displayed some allelic diversity suggests high selfing rates. We also found that the center of diversity, and by extension the origin a...