Natal dispersal is a key life history trait determining fitness and driving population dynamics, genetic structure, and species distributions. Despite existing evidence that not all phenotypes are equally likely to successfully establish in new areas, the mechanistic underpinnings of natal dispersal remain poorly understood. The propensity to disperse into a new environment can be favoured by a high degree of phenotypic plasti...

Interspecific hybridization events are on the rise in natural systems due to climate change disrupting species barriers. Across taxa, microsatellites have long been the molecular markers of choice to identify admixed individuals. However, with the advent of high‐throughput sequencing easing the generation of genome‐wide datasets, incorrect reports of hybridization resulting from microsatellite technical artefacts have been unc...

Hybridization can result in novel allelic combinations which can impact the hybrid phenotype through changes in gene expression. While misexpression in F 1 hybrids is well documented, how gene expression evolves in stabilized hybrid taxa remains an open question. As gene expression evolves in a stabilizing manner, break‐up of co‐evolved cis ‐ and trans ‐regulatory elements could lead to transgressive patterns of gene expressio...

Adaptive radiations have proven important for understanding the mechanisms and processes underlying biological diversity. The convergence of form and function, as well as admixture and adaptive introgression, are common in adaptive radiations. However, distinguishing between these two scenarios remains a challenge for evolutionary research. The Midas cichlid species complex ( Amphilophus spp.) is a prime example of adaptive ra...

Hybridization increases genetic variation, hence hybrid species may have greater evolutionary potential once their admixed genomes have stabilized and incompatibilities have been purged. Yet, little is known about how such hybrid lineages evolve at the genomic level following their formation, in particular their adaptive potential. Here we investigate how the Italian sparrow ( Passer italiae ), a homoploid hybrid species, has...

Both classical and recent studies suggest that chromosomal inversion polymorphisms are important in adaptation and speciation. However, biases in discovery and reporting of inversions make it difficult to assess their prevalence and biological importance. Here, we use an approach based on linkage disequilibrium among markers genotyped for samples collected across a transect between contrasting habitats to detect chromosomal re...

The most successful study systems are built on a foundation of decades of research on the basic biology, ecology and life history of the organisms in question. Combined with new technologies, this can provide a formidable means to address important issues in evolutionary biology and molecular ecology. Littorinid marine snails are a good example of this, with a rich literature on their taxonomy, speciation, thermal tolerance an...

Adaptation to different salinities can drive and maintain divergence between populations of aquatic organisms. Anadromous and stream ecotypes of threespine stickleback ( Gasterosteus aculeatus ) are an excellent model to explore the genetic mechanisms underlying osmoregulation divergence. Using a parapatric pair of anadromous and stream stickleback ecotypes, we employed an integrated genomic approach to identify candidate gene...

Parallel speciation occurs when selection drives repeated, independent adaptive divergence that reduces gene flow between ecotypes. Classical examples show parallel speciation originating from shared genomic variation, but this does not seem to be the case in the rough periwinkle ( L ittorina saxatilis ) that has evolved considerable phenotypic diversity across Europe, including several distinct ecotypes. Small ‘wave’ ecotype...

Sexual dimorphism can evolve when males and females differ in phenotypic optima. Genetic constraints can, however, limit the evolution of sexual dimorphism. One possible constraint is derived from alleles expressed in both sexes. Because males and females share most of their genome, shared alleles with different fitness effects between sexes are faced with intralocus sexual conflict. Another potential constraint is derived fro...