My research focuses on the evolutionary mechanisms that influence genetic variability and its relation to phenotype at the genome level and across space. It spans several timescales, from intra-population microevolutionary mechanisms to the divergence process that can eventually lead to the formation of new species. To address these different levels, I use concepts and analytical methods from the field of population genetics and apply them to polymorphism data produced with high-throughput sequencing technologies. My approach aims at extracting information from genomic Big Data to reconstruct important pages of the history of species. These reveal in particular the impact of past climate change on the contemporary biodiversity of marine fishes, which are my main research models. Although essentially fundamental, this research has applications in aquaculture genetic improvement programs and for the conservation and management of natural populations.