Species competing for resources also commonly share predators. While competition often drives divergence between species, the effects of shared predation are less understood. Theoretically, competing prey species could either diverge or evolve in the same direction under shared predation depending on the strength and symmetry of their interactions. We took an empirical approach to this question, comparing antipredator and trop...

Chromosomal inversions are often thought to facilitate local adaptation and population divergence because they can link multiple adaptive alleles into non‐recombining genomic blocks. Selection should thus be more efficient in driving inversion‐linked adaptive alleles to high frequency in a population, particularly in the face of maladaptive gene flow. But what if ecological conditions and hence selection on inversion‐linked al...

Females and males within a species commonly have distinct reproductive roles, and the associated traits may be under perpetual divergent natural selection between the sexes if their sex‐specific control has not yet evolved. Here, we explore whether such sexually antagonistic selection can be detected based on the magnitude of differentiation between the sexes across genome‐wide genetic polymorphisms by whole‐genome sequencing...

Understanding the distribution of crossovers along chromosomes is crucial to evolutionary genomics because the crossover rate determines how strongly a genome region is influenced by natural selection on linked sites. Nevertheless, generalities in the chromosome‐scale distribution of crossovers have not been investigated formally. We fill this gap by synthesizing joint information on genetic and physical maps across 62 animal,...

Genetic differentiation between divergent populations is often greater in chromosome centres than peripheries. Commonly overlooked, this broadscale differentiation pattern is sometimes ascribed to heterogeneity in crossover rate and hence linked selection within chromosomes, but the underlying mechanisms remain incompletely understood. A literature survey across 46 organisms reveals that most eukaryotes indeed exhibit a reduce...

Disentangling the processes and mechanisms underlying adaptive diversification is facilitated by the comparative study of replicate population pairs that have diverged along a similar environmental gradient. Such a setting is realized in a cichlid fish from southern Lake Tanganyika, Astatotilapia burtoni , which occurs within the lake proper as well as in various affluent rivers. Previously, we demonstrated that independent la...

Parallel adaptation is common and may often occur from shared genetic variation, but the genomic consequences of this process remain poorly understood. We first use individual‐based simulations to demonstrate that comparisons between populations adapted in parallel to similar environments from shared variation reveal a characteristic genomic signature around a selected locus: a low‐divergence valley centred at the locus and fl...

Heterogeneity in recombination rate may strongly influence genome evolution and entail methodological challenges to genomic investigation. Nevertheless, a solid understanding of these issues awaits detailed information across a broad range of taxa. Based on 282 F 2 individuals and 1872 single nucleotide polymorphisms, we characterize recombination in the threespine stickleback fish genome. We find an average genome‐wide recomb...

Evolutionary diversification is often initiated by adaptive divergence between populations occupying ecologically distinct environments while still exchanging genes. The genetic foundations of this divergence process are largely unknown and are here explored through genome scans in multiple independent lake–stream population pairs of threespine stickleback. We find that across the pairs, overall genomic divergence is associate...

Adaptation to ecologically distinct environments can coincide with the emergence of reproductive barriers. The outcome of this process is highly variable and can range along a continuum from weak population differentiation all the way to complete, genome‐wide divergence. The factors determining how far diverging taxa will move along this continuum remain poorly understood but are most profitably investigated in taxa under repl...