Genetic depletion does not prevent rapid evolution in island-introduced lizards

Experimental introductions of species have provided some of the most tractable examples of rapid phenotypic changes, which may reflect plasticity, the impact of stochastic processes, or the action of natural selection. Yet to date, very few studies have investigated the neutral and potentially adaptive genetic impacts of experimental introductions. We dissect the role of these processes in shaping the population differentiation of wall lizards in three Croatian islands (Sušac, Pod Kopište, Pod Mrčaru), including the islet of Pod Mrčaru where experimentally introduced lizards underwent rapid (~30 generations) phenotypic changes associated to a shift from an insectivorous to a plant-based diet. Using a genomic approach (~82,000 ddRAD loci), we confirmed a founder effect during introduction, and very low neutral genetic differentiation between the introduced population and its source. However, genetic depletion did not prevent rapid population growth, as the introduced lizards exhibited po...