Abstracts (first author)
Ecologically driven morphological and genetic divergence between sheltered and exposed populations of the marine snail Littorina fabalis
It is well established that ecology plays a critical role in the process of population divergence and ultimately in speciation. Nonetheless, our understanding of how it occurs is still scarce. Characterized by abrupt changes in the environmental conditions over a narrow spatial scale, the marine intertidal is an ideal system to provide valuable insights into the field of ecological speciation. In our study, we focus on North Atlantic populations of the flat periwinkle Littorina fabalis to explore to what extent adaptation and genetic divergence are promoted by contrasting wave exposure intensities and other associated factors. We analysed shell morphology and performed a genomic scan based on AFLP loci to estimate divergence between sheltered and exposed populations of L. fabalis at both micro (<40 Km) and macro-geographic (>1000 Km) scales. With this nested sampling approach, we aim to quantify phenotypic differentiation and to identify loci under disruptive selection among L. fabalis populations subject to different selective pressures in a repetitive manner along the species range. Doing so, we hope to shed light on the genetic mechanisms of ecotype evolution and ecological speciation, ultimately contributing to discern how repeatable (parallel) is divergent evolution in L. fabalis.