Genetic structure and connectivity between populations of two common Mediterranean sessile invertebrates
Nome Cognome
Stefano Tassinari
Contatto
campusravenna.segdidaambientemare@unibo.it
Relatore/Correlatore
Prof.Abbiati Marco
Dott.ssa Costantini Federica/Dott.ssa Villamor Adriana
Ente e Laboratorio di Ricerca
Asbtract
Population genetic and phylogeography of two common Mediterranean species in 10 localities distributed in three regions (Toscana, Puglia, Calabria) were studied in order to verify the extent of genetic breaks, recognized as boundaries of some biogeographical Mediterranean sectors. From about 100 sequences obtained from the mitochondrial Cytochrome Oxidase subunit I (COI) gene of Halocynthia papillosa and Hexaplex trunculus were analyzed genetic diversity, genetic structure at small and great distances and demographic history of both species, so were not found for the two species evidences of genetic breaks in Toscana and Puglia. The genetic structure of H. trunculus evidences the extent of a barrier to gene flow localized on Calabria, which could be represented by the Siculo-Tunisian Strait and the Strait of Messina. These patterns observed evidence similar level of gene flow at small distances for both species although the two species have different larval characteristics. There should be other physical factors as currents, local dynamics and seasonal temperatures influencing the connectivity along the Italian peninsula. The geographic distribution of the haplotypes evidences that H. papillosa could represent a single genetic pool in expansion, whereas H. trunculus has two distinct genetic pools in expansion. The demographic pattern of the two species suggests the influence of Pleistocene sea level oscillations, in particular of the LGM, on distribution and genetic structure of the two species. These knowledge cold represent some basic information regarding management plans, to better design specific protected areas along the Italian peninsula.
