A European Concern? Genetic Structure and Expansion of Golden Jackals (Canis aureus) in Europe and the Caucasus.

In the first continent-wide study of the golden jackal (Canis aureus), we characterised its population genetic structure and attempted to identify the origin of European populations. This provided a unique insight into genetic characteristics of a native carnivore population with rapid large-scale expansion. We analysed 15 microsatellite markers and a 406 base-pair fragment of the mitochondrial control region. Bayesian-based and principal components methods were applied to evaluate whether the geographical grouping of samples corresponded with genetic groups. Our analysis revealed low levels of genetic diversity, reflecting the unique history of the golden jackal among Europe's native carnivores. The results suggest ongoing gene flow between south-eastern Europe and the Caucasus, with both contributing to the Baltic population, which appeared only recently. The population from the Peloponnese Peninsula in southern Greece forms a common genetic cluster with samples from south-eastern Europe (ΔK approach in STRUCTURE, Principal Components Analysis [PCA]), although the results based on BAPS and the estimated likelihood in STRUCTURE indicate that Peloponnesian jackals may represent a distinct population. Moreover, analyses of population structure also suggest either genetic distinctiveness of the island population from Samos near the coast of Asia Minor (BAPS, most STRUCTURE, PCA), or possibly its connection with the Caucasus population (one analysis in STRUCTURE). We speculate from our results that ancient Mediterranean jackal populations have persisted to the present day, and have merged with jackals colonising from Asia. These data also suggest that new populations of the golden jackal may be founded by long-distance dispersal, and thus should not be treated as an invasive alien species, i.e. an organism that is "non-native to an ecosystem, and which may cause economic or environmental harm or adversely affect human health". These insights into the genetic structure and ancestry of Baltic jackals have important implications for management and conservation of jackals in Europe. The golden jackal is listed as an Annex V species in the EU Habitats Directive and as such, considering also the results presented here, should be legally protected in all EU member states.

Comparative quantitative study of the intrinsic cardiac ganglia and neurons in the rat, guinea pig, dog and human as revealed by histochemical staining for acetylcholinesterase.

This study was conducted to determine the overall number of intrinsic neurons distributed through-out the entire heart, in which most neurons are located inside of intramural ganglia and are hidden to observers. For this reason, we attempted to ascertain: (1) how the number of neurons located inside of intrinsic cardiac ganglion is related to its area, and (2) whether this relationship is dependent on age and species of animals. Hearts of rats, guinea pigs, dogs and humans were used to examine intramural ganglia stained histochemically for acetylcholinesterase (AChE). The number and parameters of neurons located inside of 104 ganglia were estimated in serial sections. Although the revealed intrinsic cardiac ganglia varied extremely in shape and size, two different types were identified: the globular and plain ones. In the plain ganglia, perikarya of side by side situated neurons were always intensely stained for AChE and, being clearly discernible, they could be reliably counted in any plain ganglia on total heart preparations using a contact microscope. Contrarily, neuron somata in the globular ganglia were densely packed above one another and their perikarya were almost indiscernible for the observer. Counting of neurons located inside of globular ganglia was possible in serial sections only. The largest cardiac ganglia were revealed in dogs, in which some globular ganglia containing up to 2000 neurons occupied more than 1 mm2. In spite of evident species-dependent differences with respect to frequency of large ganglia, the majority of intrinsic cardiac ganglia both in humans and animals were comparatively small, involved approximately 100-200 nerve cells and occupied an area ranging from 0.01 to 0.17 mm2. Overall, the number of neurons located inside of globular ganglion was related to its area (correlation coefficient = 0.82). However, the correlation coefficients between the globular ganglion area and its neuron number were unequal in different species (0.92 in guinea pig; 0.80 in dog; 0.72 in human; and 0.44 in rat) as well as dependent on (1) ganglion size (0.8 for ganglia equal to or larger than 0.17 mm2 and 0.6 for ganglia smaller than 0.17 mm2) and (2) age of specimens (respectively, 0.98 for juvenile and 0.87 for adult dogs; 0.71 for infants and 0.54 for aged human). In all examined animals and humans, the mean measurements of neuron perikarya were similar (on average, 23 microm in width, 32 microm in length, and 615 microm2 in area) and differences between them were statistically insignificant. However, neuron perikarya of adult dogs and aged humans were significantly larger than those revealed in the juvenile dogs and infants, respectively. Based on the data of this study, we concluded that the number of intrinsic cardiac neurons may be approximated in the total heart preparation via counting and measuring of intramural ganglia, contours of which are well-discernible following a histochemical reaction for AChE.