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wave exposures, and variability of chemical-physic parameters over short vertical distances
(Beaumont & Wei 1991; Nolan 1991 ; Corte-Rea! et al. 1996; Mauro et al. 2003). Indeed,
these authors pointed to the existence of a high morphological plasticity in the genus
Patella, leading to ecophenotypes largely determined by environmental conditions (De
Wolf et al. 2000; Titselaar 1998; Johannesson 2003; Pagarete 2005). The result of such
ecologica! plasticity is that, at each locality, the coexisting species under the influence of
environmental selection tend to converge morphologically, till they become hardly
distinguishable. Conversely, individuals ofthe most widespread species, P. uiyssiponensis
s.i. from different geographical areas, may be extremely dissimilar.
Ali these facts led different authors (i.a. , Mauro et al. 2003; Sa-Pinto et al. 2005; Casu et
al. 20 l O) to suggest the necessity of a genetic approach, in order to distinguish the four
Patella species. Therefore, the PCR-RFLP method provided in the present study offers a
rapid and alternative molecular tool that could be routinely used for an unambiguous
taxonomic distinction of P. uiyssiponensis s.i. from P. caeruiea, P. vulgata and P. candei,
when the morphology offers discordant or incomplete information. In this context it may
be highlighted that, although so far no study showed hybridisation between P.
uiyssiponesis and the other three species, further molecular analysis using multilocus
nuclear markers should be advisable to shed more light on this possibility.
Sequences used to design restriction sites (Table l) belong to individuals from locations
that almost completely cover the geographical distribution of the species analysed. Thus,
we may expect that Taql produces an identica! banding pattem throughout the whole
distribution range.
The strength ofthe RFLP analysis for the taxonomic attribution of P. ulyssiponesis s.i. has
been proven by the consistency with the COI sequencing results. In fact it was observed
that both the methods converged in attribute the same individuals to the species

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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 MOLECOLARI 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