Analisi della variabilità genetica di <i>Patella ferruginea</i>, <i>Patella ulyssiponensis</i> (Mollusca: Gastropoda) e <i>Pinna Nobilis</i> (Mollusca: Bivalvia): il contributo dei dati olecolari alla conservazione di specie minacciate = Analysis of the genetic variability of <i>Patella ferruginea</i>, <i>Patella ulyssiponensis</i> (Mollusca: Gastropoda) and <i>Pinna nobilis</i> (Mollusca: Bivalvia): contribution of molecular data in threatened species conservation studies

All around the planet the endangered species are precipitately disappearing as direct or indirect results of anthropization. In spite of it these species now require human assistance to improve their chances of survival and population recovery. Genetic resources play an important role as the amount of genetic diversity may influence the extinction risk, and hence they require an appropriate management. Conservation genetics encompasses genetic management of these threatened populations, resolution of taxonomic uncertainties and the use of molecular tools in order to study genetic patterns or processes that informs conservation efforts. Mitochondrial DNA partial sequencing, DNA fingeprinting by means of ISSR markers (Inter Simple Sequence Repeats), RFLP-PCR and genotyping of microsatellites and DNA barcoding were used to quantify the patterns and the amount of genetic diversity at both intra- and inter-specific level. The following articles (published, accepte, submitted or in prep.) illustrate the use of these molecular tools to investigate genetic structuring in the whole distribution range of Patella ferruginea, Patella ulyssiponensis and Pinna nobilis, three threatened species of molluscs (two gastropod and a bivalve respectively) endemic to the Mediterranean Sea. Finally, we have also studied the variability of allochthonous Ruditapes phillipinarum recently introduced in Sardinia

Determinazione specifica di individui giovanili del genere <i>Patella</i> fissati su adulti di <i>Patella ferruginea</i> (Gmelin, 1791), tramite utilizzo del DNA barcoding = Specific attribution of juveniles belonging to tehe genus <i>Patella</i> set on adults of <i>Patella ferruginea</i> (Gmelin, 1791) by means of DNA barcoding

A genetic analysis was performed on two individuals belonging to the genus Patella recovered as epibionti on P. ferruginea (Gmelin, 1791). The survey was carried out by means of the Cytochrome c Oxidase (COI) Folmer’s region. Results obtained evidenced the occurrence of a juveniles of P. ferruginea and one of P. rustica, and confirmed that COI is an invaluable tool for the DNA barcoding

Mitochondrial DNA reveals genetic structuring of <i>Pinna nobilis</i> across the Mediterranean Sea

Pinna nobilis is the largest endemic Mediterranean marine bivalve. During past centuries, various human activities have promoted the regression of its populations. As a consequence of stringent standards of protection, demographic expansions are currently reported in many sites. The aim of this study was to provide the first large broad-scale insight into the genetic variability of P. nobilis in the area that encompasses the western Mediterranean, Ionian Sea, and Adriatic Sea marine ecoregions. To accomplish this objective twenty-five populations from this area were surveyed using two mitochondrial DNA markers (COI and 16S). Our dataset was then merged with those obtained in other studies for the Aegean and Tunisian populations (eastern Mediterranean), and statistical analyses (Bayesian model-based clustering, median-joining network, AMOVA, mismatch distribution, Tajima’s and Fu’s neutrality tests and Bayesian skyline plots) were performed. The results revealed genetic divergence among three distinguishable areas: (1) western Mediterranean and Ionian Sea; (2) Adriatic Sea; and (3) Aegean Sea and Tunisian coastal areas. From a conservational point of view, populations from the three genetically divergent groups found may be considered as different management units

Analysis of the genetic variability of <i>Patella ferruginea</i> Gmelin, 1791 (Gastropoda: Patellidae) populations from the North-East Sardinia = Analisi della variabilità genetica in popolazioni di <i>Patella ferruginea</i> Gmelin, 1791 (Gastropoda: Patellidae) provenienti dalla Sardegna nord-orientale

The mollusc Patella ferruginea (Gastropoda, Patellidae), endemic to the Medilerranean, is the most endangered marine species on the list of the European Couneil Directive 92/43/EEC and it is presently under serious risk of extinction. This research was aimed to unravel the genetic variability of some Sardinian populations sampled on the North-Eastern coast, in order to shed light on their status of conservation

The Role of a marine protected area in safeguarding the genetic diversity of rare species: the case of <i>Patella ferruginea</i> Gmelin, 1791 (Gastrpoda: Patellidae) = Il Ruolo delle aree marine protette per la salvaguardia della diversità genetica di specie rare: il caso di <i>Patella ferruginea</i> Gmelin, 1791 (Gastropoda: Patellidae)

Patella ferruginea (Gastropoda: Patellidae) is an endangered marine gastropod, distributed on the western Mediterranean coasts, whose range has progressively contracted, due to intense human exploitation. Our attention focused on its genetic structure, in order to gather information about levels of genetic variability of P. ferruginea from the Asinara Marine Protected Area and a neighbouring non-protected area

Mendelian breeding units <i>versus</i> standard sampling strategies: mitochondrial DNA variation in southwest Sardinia

We report a sampling strategy based on Mendelian Breeding Units (MBUs), representing an interbreeding group of individuals sharing a common gene pool. The identification of MBUs is crucial for case-control experimental design in association studies. The aim of this work was to evaluate the possible existence of bias in terms of genetic variability and haplogroup frequencies in the MBU sample, due to severe sample selection. In order to reach this goal, the MBU sampling strategy was compared to a standard selection of individuals according to their surname and place of birth. We analysed mitochondrial DNA variation (first hypervariable segment and coding region) in unrelated healthy subjects from two different areas of Sardinia: the area around the town of Cabras and the western Campidano area. No statistically significant differences were observed when the two sampling methods were compared, indicating that the stringent sample selection needed to establish a MBU does not alter original genetic variability and haplogroup distribution. Therefore, the MBU sampling strategy can be considered a useful tool in association studies of complex traits

Standardization of inter simple sequence repeat technique to estimate genetic variability of <i>Ruditapes decussatus</i> = Standardizzazione della tecnica inter simple sequence repeat per studiare la variabilità genetica di <i>Ruditapes decussatus</i>

Ruditapes decussatus (L., 1758) is a bivalve autochthonous of the Mediterranean. We focused on the possible use of the ISSR technique to investigate its genetic variability. We tested four primers on 15 specimens from three northern Sardinian sites. We evidenced that i) ISSRs can detect satisjactory levels of genetic variability and ii) produce replicable and easily scorable results

Mendelian breeding units versus standard sampling strategies: Mitochondrial DNA variation in southwest Sardinia

We report a sampling strategy based on Mendelian Breeding Units (MBUs), representing an interbreeding group of individuals sharing a common gene pool. The identification of MBUs is crucial for case-control experimental design in association studies. The aim of this work was to evaluate the possible existence of bias in terms of genetic variability and haplogroup frequencies in the MBU sample, due to severe sample selection. In order to reach this goal, the MBU sampling strategy was compared to a standard selection of individuals according to their surname and place of birth. We analysed mitochondrial DNA variation (first hypervariable segment and coding region) in unrelated healthy subjects from two different areas of Sardinia: the area around the town of Cabras and the western Campidano area. No statistically significant differences were observed when the two sampling methods were compared, indicating that the stringent sample selection needed to establish a MBU does not alter original genetic variability and haplogroup distribution. Therefore, the MBU sampling strategy can be considered a useful tool in association studies of complex traits

Preliminary data on the genetic variability of the fan mussel <i>Pinna nobilis</i> in the Northern Sardinia = Dati preliminari sulla variabilità genetica del mollusco bivalve <i>Pinna nobilis</i> nella Sardegna settentrionale

The fan mussel Pinna nobilis Linnaeus, 1758 is one of the most endangered Mediterranean bivalve. After a reduction of its distribution as a consequence of anthropic factors, the environmental politics led to a new demographic increasing of individuals in some Mediterranean regions. This work aimed to shed some light on the genetic structure of two new-raised populations in northern Sardinia

PCR-RFLP: a practical method for the identification of specimens of <i>Patella ulyssiponensis s.l.</i> (Gastropoda: <i>Patellidae</i>)

Patella ulyssiponensis s.l. is widely distributed in the Mediterranean as well as in the north-eastern Atlantic, from southern Norway to north-western Africa, including Macaronesia. Throughout its range, P. ulyssiponensis s.l. shows a high degree of variability in the shape and colour pattern of the shell and in the colour pattern of the foot. In addition, the species demonstrates widely overlapping morphological parameters with the coexisting P. caerulea (in the Mediterranean), P. vulgata (in north-eastern Atlantic) and P. candei (in the Macaronesian islands). Thus P. ulyssiponensis s.l. identification proves to be difficult. So far, method to unequivocally identify uncertain specimens of P. ulyssiponensis s.l. from the coexisting species was using a molecular taxonomy approach based on the Cytochrome c Oxidase subunit I (COI) sequences analysis. The aim of the present study was to identify specific PCR-RFLP (Restriction Fragment Length Polymorphism PCR-based) markers on the COI sequences which could be used as an alternative and fast diagnostic tool for the discrimination of P. ulyssiponensis s.l. from P. caerulea, P. vulgata and P. candei, when the morphology of the coexisting individuals provided equivocal information. First, we sampled 65 Patella spp. and classified these by means of the COI sequencing. Then, we selected the TaqI endonuclease for the specific RFLP reaction, which produced a combination of RFLP electrophoretic bands, allowing an unequivocal identification of the individuals of P. ulyssiponensis s.l.</i