Population genetic studies are efficient for inferring the invasion history based on a comparison of native and invasive populations, especially when conducted at species scale. An expected outcome in invasive populations is variability loss, and this is especially true in self-fertilizing species. We here focus on the self-fertilizing Pseudosuccinea columella, an invasive hermaphroditic freshwater snail that has greatly expanded its geographic distribution and that acts as intermediate host of Fasciola hepatica, the causative agent of human and veterinary fasciolosis. We evaluated the distribution of genetic diversity at the largest geographic scale analysed to date in this species by surveying 80 populations collected during 16 years from 14 countries, using eight nuclear microsatellites and two mitochondrial genes. As expected, populations from North America, the putative origin area, were strongly structured by selfing and history and harboured much more genetic variability than invasive populations. We found high selfing rates (when it was possible to infer it), none-to-low genetic variability and strong population structure in most invasive populations. Strikingly, we found a unique genotype/haplotype in populations from eight invaded regions sampled all over the world. Moreover, snail populations resistant to infection by the parasite are genetically distinct from susceptible populations. Our results are compatible with repeated introductions in South America and flash worldwide invasion by this unique genotype/haplotype. Our study illustrates the population genetic consequences of biological invasion in a highly selfing species at very large geographic scale. We discuss how such a large-scale flash invasion may affect the spread of fasciolosis.
|Number of pages||17|
|State||Published - 1 Feb 2017|
Bibliographical noteFunding Information:
Part of this work has been supported by University of Montpellier (?contrat doctoral? fellowship to ML), by IRD (financial support, grant BSTD to ACC and grant BEST to AAV), by CNRS and LABEX Cemeb (financial support). PD, PJ and JPP are supported by the Bio-Adapt program (ANR ESHAP). We are most grateful to P. Alda, P. Durand, R. Gozlan and F. Renaud for helpful discussions, to three referees for comments and to Ananda Christophe for technical help.
© 2016 John Wiley & Sons Ltd
- Fasciola hepatica
- Pseudosuccinea columella
- biological invasion
- liver fluke
- mitochondrial markers
- population genetics