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Sardinia (SAR), Sicily (SIC), Elba Island (ELB), Venetian Lagoon (VL), Cyprus (CIP),
our Tunisian sample (BIZ), Greece (GRE) and Tunisia (TUN) (Fig. 2b), no haplotype
was shared between Tunisian and Grecian samples and the other populations.

The Bayesian analysis evidenced the occurrence of four distinct groups of
haplotypes (Pl, P2, P3 and P4). When displayed on the network graphic, each ofthern
appears characterised by one or two main haplotypes with derived variability set in a
star-like network configuration (Fig. 3). Three of the rnitochondrial COI haplogroups
found (Pl, P2 and P3) belong to the samples from Sardinia, Sicily, Elba Island,
Venetian Lagoon and to the single Tunisian individuai (BIZ) from our dataset without
evidence of geographic structuring, while ali the other sarnples frorn Tunisia and Greece
belong to the fourth group (P4) with the exception of one Grecian individuai from
Epanorni and three Tunisian specimens frorn Monastir which grouped with P2 and P3
haplogroups respectively.

The interpolation of haplogroups' frequencies (Table 3) over the Mediterranean
map gives a snapshot of their potential geographic distribution (Fig. 4) . The haplogroup
P l is spans across the western Mediterranean, reachs Sicily and spreads into the Ionian
sea. The haplogroup did not display a gradient of decreasing frequencies as higher
values were found in northem Sardinia, and in both North-West and South-East of
Sicily (Fig. 4a). Tough the haplogroup P2 is the rnost geographically spread across the
whole Mediterranean basin it displays a lower average frequency than P l (0.22 and
0.30, respectively. It reaches its higher frequencies in areas as far as northern Adriatic
sea and Sardinian sea (Oristano, western Sardinia) (Fig. 4b). The haplogroup P3 spreads
in western Mediterranean, Sicily, Adriatic Sea and sporadically in Tunisia (two
individuals frorn Monastir), and it is characterised by the lowest average frequency
(0.06).. Its higher leve) offrequency correspond to the Elba Island, Molara in the North-

58

Gìan Luca Dedola: ANALISI DELLA VARIABILITÀ GENETICA DI PATELLA FéRRUGINEA, PATEL-LA UL l'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