My research group is studying (i) the evolution of sex chromosomes in Sylvioidea songbirds, (ii) speciation in Nesospiza finches, and (iii) hybridization in damselflies. We have chosen these systems because Sylvioidea songbirds exhibit the most dynamic and recently evolved sex chromosomes known to date among birds, which provides unique opportunities to understand how sex chromosomes evolve in vertebrates in terms of degeneration, repeat accumulation, gene loss and gene expression. The clade is species-rich which makes it possible to use comparative approaches to link the rate of sex chromosome evolution to the evolution of sexual dimorphism, and there are interesting parallels to mammals as Sylvioidea birds and mammals share a homologous region of their sex chromosomes (a situation not found in any other bird clade). Nesospiza finches on the Tristan da Cunha archipelago in the South Atlantic constitute an ongoing radiation driven by adaptation to divergent food sources, and we study this system to understand how a few large-effect mutations can contribute to extreme trait variation associated with food preference, habitat selection and assortative mating in speciating taxa. Finally, we are studying a pair of damselfly sister species in Spain to understand the genomic consequences of hybridization and differential introgression on autosomes and sex chromosomes.