Population genetic structure in a human-disturbed environment: a case study in the land snail Helix aspersa (Gastropoda: Pulmonata)

Abstract

Local patterns of genetic variation were analysed in the land snail Helix aspersa for 32 populations sampled within a patchy agricultural landscape: the polders of the Bay of Mont-Saint-Michel (France). This investigation examined the allele frequencies at four enzymatic markers and five microsatellite loci through the genotyping of 580 individuals. A strongly significant population genetic substructuring (mean F ST ¼ 0.088, Po0.001) was found at the scale of the whole polders area (3050 ha) and both categories of markers displayed a similar magnitude of spatial genetic differentiation. We did not find any obvious effects of habitat fragmentation on the distribution of genetic variability. Despite the reality of habitat patchiness and environmental instability (related to farming practices), an isolation by distance process was clearly depicted, although selective pressures cannot be ruled out for one enzymatic locus. Overall, genetic drift, along with occasional long-distance episodes of gene flow, was presumably the most likely evolutionary force that shaped the observed pattern of genetic variation.

Genetic structure of the whitefly Bemisia tabaci in the Asia–Pacific region revealed using microsatellite markers

“…Studies on genetic structure in agriculture landscapes that are characterized by habitat fragmentation and patch environmental instability are few. Arnaud et al . (2003) found increasing genetic divergence with respect to distance among geographically separated populations for the snail Helix aspera in the reclaimed land on the Bay of Mont‐Saint‐Michele despite habitat fragmentation and patch environmental instability.…”

The Complete Mitochondrial Genome of the Land Snail Cornu aspersum (Helicidae: Mollusca): Intra-Specific Divergence of Protein-Coding Genes and Phylogenetic Considerations within Euthyneura

“…Here we report the mitochondrial genome of three individuals of the land snail Cornu aspersum , one of the most widespread invasive species in the world [19], [20]. This species is native from the West Mediterranean, and since the Holocene has successfully colonized all continents except Antarctica [21].…”

Rangewide phylogeography of a terrestrial slug in Europe: evidence for Alpine refugia and rapid colonization after the Pleistocene glaciations

“…1996), have low active dispersal abilities. Molecular work on Helix aspersa (Arnaud et al . 2001, 2003) and Cepaea nemoralis (Davison & Clarke 2000) has also shown that populations are highly structured and that isolation by distance is prevalent.…”

“…2001, 2003) and Cepaea nemoralis (Davison & Clarke 2000) has also shown that populations are highly structured and that isolation by distance is prevalent. Although passive dispersal and rare cases of long‐distance dispersal (Arnaud et al . 2001, 2003) may partly compensate for the lack of active dispersal capacities, the Pleistocene climatic oscillations resulted in the range restriction of most pulmonate gastropods (Hausdorf & Hennig 2003; Pfenninger 2004).…”