Climate change and population genetic structure ofmarine species

Climate change influences populations by reducing or extirpating local populations, by disrupting patternsof migration and by shifting geographical distributions. These events can affect genetic populationstructure in several ways. Molecular markers have been used in numerous population genetic and phylogeographicalstudies of marine species and have detected population responses to climate change in thelast few decades, such as range expansions, adaptative shifts and declines or increases in abundance. Littleis known, however, about the molecular and physiological basis of adaptive responses to climate changein marine Mediterranean species. The Mediterranean Sea ecosystem is a ‘living laboratory’ with nativespecies that are challenged by environmental change and by invasive species and a ‘gene-climate’approachshould be adopted as a way of focusing on the relationship between climate warming and genetic diversity.