Genetic variability and differentiation in the Mediterranean endemic starry ray Raja asterias (Delaroche, 1809)

Gerotto, Valentina (2013) Genetic variability and differentiation in the Mediterranean endemic starry ray Raja asterias (Delaroche, 1809). [Laurea magistrale], Università di Bologna, Corso di Studio in Biologia marina [LM-DM270] - Ravenna, Documento ad accesso riservato.
Documenti full-text disponibili:
[img] Documento PDF
Full-text non accessibile

Download (1MB) | Contatta l'autore


The present study deal with the population structure and connectivity of the Mediterranean endemic starry ray Raja asterias (Delaroche, 1809) in the Western and Eastern Mediterranean basin. A panel of eight microsatellite loci which cross-amplify in Rajidae (El Nagar, 2010) was used to assess population connectivity and structure. Those aims were investigated by analyzing the genetic variation of 9 population sample for a total of 185 individuals collected during past scientific surveys (MEDITS, GRUND), commercial trawling and also directly at fish markets. The purpose of this thesis is to estimate the genetic divergence occurring between the Mediterranean populations and, in particular, to assess the presence of any barrier (geographic, hydrogeological and biological) to gene flow for this species. Different statistical approaches were performed to reach this aim evaluating both the genetic diversity (nucleotide diversity, allelic richness, observed and expected heterozygosity and Hardy-Weinberg equilibrium test) and the population differentiation patterns (pairwise Fst estimated and population structure analysis). The results obtained from the analysis of the microsatellite dataset suggest a geographic and genetic separation between the starry ray populations of the Mediterranean basin into three or four distinct groups: Western and Eastern Mediterranean basins and Sicilian coast always clustering as an independent group and Algeria which could be or not considered another separate group. The data were discussed from both an evolutionary and a conservation point of view and in relation to previous results obtained by the analysis of mitochondrial marker. A comparison with other Mediterranean demersal skate species was performed in order to better contextualise our results. Finally, our results could offer useful information to protect vulnerable species as R. asterias and developing effective conservation plans in the Mediterranean.

Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Gerotto, Valentina
Relatore della tesi
Corso di studio
Ordinamento Cds
Parole chiave
Raja asterias, microsatelliti, struttura di popolazione, Mediterraneo
Data di discussione della Tesi
12 Dicembre 2013

Altri metadati

Gestione del documento: Visualizza il documento