Rapid Reversion Towards Wild Population Attributes after Domesticated-Wild Hybridization in a Fish

Current conservation practices exclude human-generated hybrid populations from protection, as genetic effects of hybridization on wild populations are thought to be long-lasting and potentially irreversible. Some theory, however, predicts otherwise. We transplanted combinations of wild, hatchery and hybridized populations of a fish species to new environments. These populations were monitored to determine if the reduced survival observed among recently hybridized populations persists after multiple generations, or if natural selection possibly returns affected populations to more natural states. Our results suggest that within seven to ten generations, natural selection can remove maladaptive genes from wild populations that have hybridized with domesticated conspecifics, allowing reversion of survival, phenotypic plasticity and mean trait expression to levels comparable to closely related wild populations. These results have important implications for considering the potential conservation value of hybridized populations, and illustrate the effectiveness of selection in returning domesticated phenotypes to wild-like states.