The European wild boar is an important game species, subjected to local extinctions and translocations in the past, and currently enormously and worryingly expanding in some areas where management is urgently required. Understanding the relative roles of ancient and recent events in shaping the genetic structure of this species is therefore not only an interesting scientific issue, but it represents also the basis for addressing future management strategies. In addition, several pig breeds descend from the European wild boar, but the geographical location of the domestication area(s) and the possible introgression of pig genomes into wild populations are still open questions. Here, we analysed the genetic variation in different wild boar populations in Europe. Ten polymorphic microsatellites were typed in 252 wild boars and the mtDNA control region was sequenced in a subset of 145 individuals. Some samples from different pig breeds were also analysed. Our results, which were obtained considering also 612 published mtDNA sequences, suggest that (i) most populations are similarly differentiated, but the major discontinuity is found along the Alps; (ii) except for the Italian populations, European wild boars show the signature of a postglacial demographic expansion; (iii) Italian populations seem to preserve a high proportion of preglaciation diversity; (iv) the demographic decline which occurred in some areas in the last few centuries did not produce a noticeable reduction of genetic variation; (v) signs of human-mediated gene flow among populations are weak, although in some regions the effects of translocations are detectable and a low degree of pig introgression can be identified; (vi) the hypothesis of an independent domestication centre in Italy is not supported by our data, which in turn confirm that Central European wild boar might have represented an important source for domestic breeds. We can therefore conclude that recent human activities had a limited effect on the wild boar genetic structure. It follows that areas with high variation and differentiation represent natural reservoirs of genetic diversity to be protected avoiding translocations. In this context controlling some populations by hunting is not expected to affect significantly genetic variation in this species.
The reintroduction of wild boar from central Europe after World War II has contributed substantially to the range expansion of this species in Italy, where indiscriminate hunting in earlier times resulted in extreme demographic reduction. However, the genetic impact of such processes is not well-understood. In this study, 105 individuals from Italian and Hungarian wild boar populations were characterized for nine autosomal microsatellite loci. The Hungarian samples, and two central Italian samples from protected areas (parks) where reintroduction is not documented, were assumed to be representative of the genetic composition of the source and the target populations in the reintroduction process, respectively. Animals hunted in the wild in the Florence area of Tuscany (Italy) were then studied to identify the effects of reintroduction. The results we obtained can be summarized as follows: (i) none of the populations analysed shows genetic evidence of demographic decline; (ii) the three parental populations from Italy and Hungary are genetically distinct; however, the low level of divergence appears in conflict with the naming of the Italian and the European subspecies (Sus scrofa majori and Sus scrofa scrofa, respectively); in addition, the Italian groups appear to be as divergent from each other as they are from the Hungarian population; (iii) most of the individuals hunted near Florence are genetically intermediate between the parental groups, suggesting that hybridization has occurred in this area, the average introgression of Hungarian genotypes is 13%, but approximately 45% of the genetic pool of these individuals can not be directly attributed to any of the parental populations we analysed; (iv) analysis of microsatellite loci, though in a limited number, is an important tool for estimating the genetic effect of reintroduction in the wild boar, and therefore for the development of conservation and management strategies for this species.
The first hypervariable fragment (HVI) of the mitochondrial DNA control region was sequenced in 90 individuals of the European roe deer (Capreolus capreolus) from the Alps, central Italy and Spain. Pooling these data with 70 published sequences from several European regions, we were able to identify patterns of divergence within the Italian peninsula, and in Europe in general. The results we obtained can be summarized as follows. First, the genetic structure of European roe deer populations is substantial (PhiST values around 0.6). Second, the divergence between some central Italian populations, the Alpine group (which is genetically close to the French, the Spanish and the Norwegian samples) and the Eastern European populations seems to reflect Upper Pleistocene subdivisions, possibly related to three southern European refugia. Third, a different group of central Italian individuals probably diverged more recently from the Alpine group, and their attribution to the subspecies C. c. italicus does not appear justified. Fourth, the analysis of mitochondrial DNA in the roe deer can be used to identify recently reintroduced animals in the western Alps which clearly cluster within the Eastern European group, thus providing an important tool for conservation and management strategies for this species.
The agouti locus encodes the agouti signalling protein (ASIP) which is involved in determining the switch from eumelanin to pheomelanin synthesis in melanocytes. In the domestic rabbit (Oryctolagus cuniculus) early studies indicated three alleles at this locus: A, light-bellied agouti (wild type); a(t), black and tan; a, black nonagouti. We characterized the rabbit ASIP gene and identified the causative mutation (an insertion in exon 2) of the black nonagouti allele whose frequency was evaluated in 31 breeds. Phylogenetic analysis of ASIP sequences from Oryctolagus and 9 other species of the family Leporidae placed Oryctolagus as sister species to Pentalagus and Bunolagus. Transcription analysis in wild type agouti rabbits revealed the presence of two major transcripts with different 5'-untranslated regions having ventral or dorsal skin specific expression. ASIP gene transcripts were also detected in all examined rabbit tissues distinguishing the rabbit expression pattern from what was observed in wild type mice.
The toxin-producing microbial species Alexandrium minutum has a wide distribution in the Mediterranean Sea and causes high biomass blooms with consequences on the environment, human health and coastal-related economic activities. Comprehension of algal genetic differences and associated connectivity is fundamental to understand the geographical scale of adaptation and dispersal pathways of harmful microalgal species. In the present study, we combine A. minutum population genetic analyses based on microsatellites with indirect connectivity (C i ) estimations derived from a general circulation model of the Mediterranean sea. Our results show that four major clusters of genetically homogeneous groups can be identified, loosely corresponding to four regional seas: Adriatic, Ionian, Tyrrhenian and Catalan. Each of the four clusters included a small fraction of mixed and allochthonous genotypes from other Mediterranean areas, but the assignment to one of the four clusters was sufficiently robust as proved by the high ancestry coefficient values displayed by most of the individuals (.84%). The population structure of A. minutum on this scale can be explained by microalgal dispersion following the main regional circulation patterns over successive generations. We hypothesize that limited connectivity among the A. minutum populations results in low gene flow but not in the erosion of variability within the population, as indicated by the high gene diversity values. This study represents a first and new integrated approach, combining both genetic and numerical methods, to characterize and interpret the population structure of a toxic microalgal species. This approach of characterizing genetic population structure and connectivity at a regional scale holds promise for the control and management of the harmful algal bloom events in the Mediterranean Sea.
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