PI: Emiliano Trucchi. Partecipanti: Francesco Giannelli, Samuele Broccardo, Emanuela Fanelli, Ernesto Azzurro, Greg Skouradakis, Antonis Petrou.
Hundreds of marine species are entering the Mediterranean from the Red Sea after the opening of the Suez canal in 1869. A concerning amount of these so-called Lessepsian invaders are successfully colonising and spreading all over the basin, negatively interfering with native species. This continuous spread is also favoured by the consequences of climate change that is resulting in increased sea temperatures benefiting Lessepsian species that are better adapted to warmer environments than native species. Lessepsian invaders have been extensively studied under an ecological point of view but just a few genomics studies have been carried out so far and none of them focused on both neutral and non neutral genetic variability. This means that the ongoing adaptation processes and the dynamics of accumulation of deleterious mutations during the invasive process to date have been largely ignored, despite the fact that these dynamics are considered fundamental to understand the basis of the invasive processes and build reliable predicting models.
Using two Lessepsian fish species, Pterois miles and Siganus rivulatus, chosen for their different ecological and economic impacts and for their distinct trophic guilds, we are going to investigate the trajectories of different types of genetic variability (adaptive, deleterious and neutral), during the colonisation of new habitats, in order to answer the following questions: How did the invasion of the Mediterranean by Lessepsian species occur? And what are the dynamics of population expansion in the invasive range? Is the genetic load actually increasing during the expansion as expected? Are there ongoing selective processes acting in the invasive range? Were some of the putative genetic variants under selection in the new environment already present in the source population as possible preadaptation?
ENDEMIXIT 