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restricted to the Macaronesia. On the other hand, Sa-Pinto et al. (2005 , 2008) based
upon mtDNA data referred to continental and Macaronesian "forms" of P.
ulyssiponensis, respectively. Hence, the species range should be restricted to the
Mediterranean and the Atlantic coasts of Europe up to South Norway according to
Weber and Hawkins (2005), whereas it should be extended to Macaronesian islands
according toSa Pinto et al. (2005, 2008). Furthermore, both the sequencing
mitochondrial DNA (COI) and a PCR-RFLP assay on the same region allowed to
distinguish without uncertainty P. ulyssiponensis from the congeneric species P.
ulyssiponensis s. l. from P. caerulea, P. vulgata and P. candei (Sa Pinto et al. 2005,
2008; Sanna et al in press).
In this work we present a survey of genetic variation in the species at large geographical
scale. This study differs from former ones that were more targeted on the assessment of
species status (e.g. Weber and Hawkins 2005) or the phylogeographic pattems across
Macaronesian islands and the continent (e.g. Sa Pinto et al. 2008). Here we focus the
aim on deciphering the pattems of spatial genetic structure in the species/form spread
along the European Mediterranean and Atlantic coasts. Such information may be useful
in addressing issues related to the ecology and conservation of a species (Garrick et al.
20 10). For instance, the assessment of genetic differentiation among populations may
be used to infer species dispersa] capabilities and genetic connectivity among
populations (Kinland and Gaines 2003). Moreover, the knowledge of the amount of
genetic variability and distribution in space and time is criticai fora correct diagnosis of
the status, threats and viability of populations (Frankham 1995; Escudero et al. 2003).
To reach these goals, we used nuclear ISSR markers (Zietckiewicz et al. 1994) because
this technique is affordable and less laborious compared with other fingerprinting
methods. Simulations indicate that dominant markers, such as ISSRs, may be as

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Gìan Luca Dedola: ANALISI DELLA VARIABILITÀ GENETICA DI PATELLA FéRRUGINEA, PATEL.LA ULl'SSIPONENSIS (MOLLUSCA: GASTROPODA) E PINNA
NOBILIS (MOLLUSCA: BIVALVIA): lLCONTRJBUTO DEl DATI MOLECOLARl ALLA CONSERVAZIONE DI SPECIE MINACCIATE - Tesi di douorato in Scienze
della natura e delle sue risorse · indiri7.zo BK>logi.a Ambientale, Università degli Studi di Sassarl