After the Ice: using a hybrid zone as a window into the genes underlying species formation

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The process of species formation is responsible for the global distribution of biodiversity, from the generation of species in habitats as extreme as the arctic or deep-sea thermal vents, to the generations of crop varieties that are locally adapted to different water regimes. Yet, we still understand very little about which genes drive the formation of new species, and what the nature is of selection acting on these genes. Evolutionary genetic studies have traditionally used either experimental hybrids from species that rarely meet in nature, or hybrid zones in uncontrolled conditions, often leading to conflicting conclusions. Here, we integrate both approaches in a single biological system: two grasshopper subspecies that maintain ecomorphologic differentiation despite ongoing hybridization since the end of the last glaciation. First, we will use experimental hybrids to test which genes are associated with reproductive dysfunction. We then use a hybrid zone as a natural laboratory to test if those phenotypes and genes contribute for stable boundaries between the two species in nature. Finally, we use samples distributed over a time series, to test whether those genetic boundaries are stable over evolutionary time. Rooted sound in my background of field- and lab-based methods, this project brings together state of the art genomic methods championed by the Center for GeoGenetics (Denmark), and the multidisciplinary knowledge on this species accumulated by the Universidad Autónoma de Madrid (Spain). By moving from lab to nature and through time, this integrative framework will not only provide unique insights on the field of speciation, but will provide a transferable framework that is applicable to emergent challenges of the modern society, such as identifying genes associated with human diseases and genes underlying adaptation of crop to stringent environments.