Methods recently developed to infer population structure and admixture mostly use individual genotypes described by unlinked neutral markers. However, Hardy-Weinberg and linkage disequilibria among independent markers decline rapidly with admixture time, and the admixture signals could be lost in a few generations. In this study, we aimed to describe genetic admixture in 182 European wild and domestic cats (Felis silvestris), which hybridize sporadically in Italy and extensively in Hungary. Cats were genotyped at 27 microsatellites, including 21 linked loci mapping on five distinct feline linkage groups. Genotypes were analysed with structure 2.1, a Bayesian procedure designed to model admixture linkage disequilibrium, which promises to assess efficiently older admixture events using tightly linked markers. Results showed that domestic and wild cats sampled in Italy were split into two distinct clusters with average proportions of membership Q > 0.90, congruent with prior morphological identifications. In contrast, free-living cats sampled in Hungary were assigned partly to the domestic and the wild cat clusters, with Q < 0.50. Admixture analyses of individual genotypes identified, respectively, 5/61 (8%), and 16-20/65 (25-31%) hybrids among the Italian wildcats and Hungarian free-living cats. Similar results were obtained in the past using unlinked loci, although the new linked markers identified additional admixed wildcats in Italy. Linkage analyses confirm that hybridization is limited in Italian, but widespread in Hungarian wildcats, a population that is threatened by cross-breeding with free-ranging domestic cats. The total panel of 27 loci performed better than the linked loci alone in the identification of domestic and known hybrid cats, suggesting that a large number of linked plus unlinked markers can improve the results of admixture analyses. Inferred recombination events led to identify the population of origin of chromosomal segments, suggesting that admixture mapping experiments can be designed also in wild populations.

Papillomaviruses play an important role in human cancer development, and have been isolated from a number of animal malignancies. However, the association of papillomaviruses with tumors has been poorly investigated in sheep. In this study, a novel ovine Papillomavirus, OaPV3, was cloned from sheep squamous cell carcinoma. Unlike the already known ovine papillomaviruses, belonging to the Delta genus, OaPV3 lacks the E5 open reading frame and maintains the conserved retinoblastoma motif in the E7 gene. OaPV3 infects exclusively epithelial cells, and was found in skin of healthy sheep of geographically separated flocks located in Sardinia (Italy). This new virus is transcriptionally active in tumors and shares low homology with all the other papillomaviruses, establishing a new genus. Taken together, the co-occurrence of OaPV3 and tumors, its cell and tissue tropism, and its gene repertoire, suggests a role for this virus in development of sheep squamous cell carcinoma.

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During the last century, otter populations in the Mediterranean area of the Iberian Peninsula were dramatically reduced and disappeared in many localities. A reintroduction programme was established in north-eastern Spain (Muga and Fluvià basins and the ''Aiguamolls de l'Empordà'' wetlands), by releasing 42 otters from four different Iberian populations, between 1995 and 2002. In order to evaluate the success of the reintroduction programme, we investigated microsatellite variation in the native populations of released otters as well as in the population present in the release area in 2004. We used non-invasively collected samples as the DNA source to avoid disturbing the animals in the wild. Laboratory procedures included the screening of samples and a multipletubes approach to detect and correct genotyping errors. Our results show that founders have been replaced by descendants in the release area and the population is in HardyWeinberg equilibrium, with a 1:1 sex ratio. Western Iberian otters-representing two-thirds of the founder group and released earlier-have greatly contributed to the genetic composition of the current population. The genetic patterns of otters found in a basin north of the studied area suggest a common origin with the released population. We also detected in a few otters the presence of alleles not identified in the original founder group, and we shall discuss the possible origin of these alleles.

Free-living and captive chelonians might suffer from upper respiratory tract disease (URTD), a pathology primarily caused by Mycoplasma agassizii. Wild tortoises can also be an important reservoir of Salmonella spp., which are commensal in the host reptile but are potential zoonotic agents. Between July 2009 and June 2010, we screened free-living European tortoises (spur-thighed tortoises Testudo graeca, Hermann's tortoises Testudo hermanni, marginated tortoises Testudo marginata) temporarily housed in a wildlife center in Italy. We molecularly characterized 13 Mycoplasma isolates detected in all Testudo spp. studied, and three PCR-positive animals showed typical URTD clinical signs at the time of sampling. Three Salmonella enterica serotypes (Abony, Potsdam, Granlo), already related to reptile-associated human infections, were also identified. These results highlight the potential role played by wildlife recovery centers in the spread and transmission of pathogens among wild chelonians and to humans.

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The population genetic structure of an invasive species in Spain, the American mink (Mustela vison), was investigated using microsatellite DNA markers. This semiaquatic carnivore, originating from North America, was imported into Europe for fur farming since the beginning of the 20th century. Due to massive escapes, farm damages, deliberate releases and/or accidents, feral mink populations were established in the aquatic ecosystems of many European countries, including Spain. We genotyped 155 American mink originating from the Spanish regions Basque Country, Catalonia, Castilla-Leon, Aragon, Valencia and Galicia using 10 polymorphic microsatellite loci to highlight population genetic structure, distribution and dispersal. M. vison populations in Spain appear differentiated and not yet connected by gene flow. Bayesian clustering analyses and spatial analyses of molecular variance detected four inferred clusters, overall coinciding with the sampled geographical localities. Preliminary testing shows moderate to large estimated effective population sizes. Molecular analyses result useful to provide baseline data for further research on the evolution of invasive mink populations, as well as support local management strategies and indirectly benefit the conservation of threatened species in Spain, such as the endangered European mink (Mustela lutreola), and the polecat (Mustela putorius), which share the habitat with the American mink.

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