Slovenian Populations Research Articles

CTLA-4 +49 A/G gene polymorphism in Croatian and Slovenian multiple sclerosis patients

Polymorphisms in the CTLA-4 gene are known to be important in several autoimmune diseases, including multiple sclerosis (MS). Previous studies on the impact of CTLA-4 +49 A/G gene polymorphism have given contradictory results. We investigated the possible influence of this polymorphism on MS susceptibility and disease behaviour in Croatian and Slovenian populations. Genotyping was performed in 367 patients with MS and 480 control subjects using PCR-RFLP method. The G allele was present in 216 (58.9%) patients with MS vs. 282 (58.7%) healthy controls (P = 0.975, OR = 1.01, 95% CI = 0.76-1.32). No significant differences were observed in CTLA-4 +49 A or G allele distribution between patients and controls, indicating that this polymorphism does not influence susceptibility to MS in the surveyed populations. No correlation was observed between G allele carrier status and age at disease onset, disease course or severity.

Diversity of vegetative compatibility types and mating types of Cryphonectria parasitica in Slovenia and occurrence of associated Cryphonectria hypovirus 1

Cryphonectria parasitica, the causal agent of chestnut blight, has been present in Slovenia since at least 1950. To improve understanding of its diversity, 254 isolates of the fungus from 11 Slovenian populations were sampled. Fifteen vegetative compatibility (vc) types were identified. The dominant vc type was EU‐13, comprising 40·1% of all isolates tested, followed by EU‐1 (19·7%), EU‐2 (12·2%) and EU‐12 (9%). The vc type diversity in the most diverse population sampled in Slovenia was higher than in the populations found previously in northern Italy and Croatia. Both mating types and perithecia were observed in surveyed populations. Natural hypovirulence was found in six out of seven populations tested, with frequencies ranging from 72·2% in the population sampled near the Croatian border to 11·1% in the population sampled near the Austrian border. All identified hypoviral isolates (21) belonged to the Italian subtype of Cryphonectria hypovirus 1 and were closely related to the hypoviruses found in other European countries. Despite the high vc type diversity, incidence of hypovirulence was also high, indicating widespread natural biological control of the disease.

Facial Morphology of Slovenian and Welsh White Populations Using 3-Dimensional Imaging

To use 3-dimensional (3D) facial averages to test the hypothesis that the facial morphologies of 2 European white groups (Slovenia and Wales) have no differences. Fifty males and 50 females from Wales and 43 males and 44 females from Slovenia were included in the study. Subjects ranged from 18 to 30 years of age. Four subgroups were formed: Slovenian males (SM), Slovenian females (SF), Welsh males (WM), and Welsh females (WF). 3D data were acquired using a laser scanning system. An average face for each subgroup was obtained using a previously validated mathematical algorithm. Facial differences were quantified after average faces had been superimposed using a previously validated method. A total of 187 subjects from Slovenia and Wales formed 4 gender-specific subgroups. Absolute differences between subgroups ranged from 0.36 mm to 1.51 mm. The mean linear facial difference between SF and WF was 0.64 +/- 0.51 mm, and between SM and WM was 0.36 +/- 0.41 mm. Similarities between subgroups ranged from 13.43% (SF, WF) to 70.23% (SM, WM). Slovenian males and females tend to express Class III facial morphology when compared with the Welsh gender-specific subgroups. Male faces, in general, have more pronounced nasal, brow, and frontal regions and mandibles when compared with females. Female faces have more prominent malar and periocular areas. The hypothesis is rejected. Morphologic differences exist between Slovenian and Welsh faces.

HLA‐A, ‐B, ‐C, and ‐DRB1 allele and haplotype frequencies distinguish Eastern European Americans from the general European American population

Sequence-based typing was used to identify human leukocyte antigen (HLA)-A, -B, -C, and -DRB1 alleles from 558 consecutively recruited US volunteers with Eastern European ancestry for an unrelated hematopoietic stem cell registry. Four of 31 HLA-A alleles, 29 HLA-C alleles, 59 HLA-B alleles, and 42 HLA-DRB1 alleles identified (A*0325, B*440204, Cw*0332, and *0732N) are novel. The HLA-A*02010101g allele was observed at a frequency of 0.28. Two-, three-, and four-locus haplotypes were estimated using the expectation-maximization algorithm. The highest frequency extended haplotypes (A*010101g-Cw*070101g-B*0801g-DRB1*0301 and A*03010101g-Cw*0702-B*0702-DRB1*1501) were observed at frequencies of 0.04 and 0.03, respectively. Linkage disequilibrium values (Dij') of the constituent two-locus haplotypes were highly significant for both extended haplotypes (P values were less than 8 x 10(-10)) but were consistently higher for the more frequent haplotype. Balancing selection was inferred to be acting on all the four loci, with the strongest evidence of balancing selection observed for the HLA-C locus. Comparisons of the A-C-B haplotypes and DRB1 frequencies in this population with those for African, European, and western Asian populations showed high degrees of identity with Czech, Polish, and Slovenian populations and significant differences from the general European American population.

Values of young people in Slovenia

In this article the values and life orientation of young people in Slovenia over a recent 10-year period are analysed. As is the case in the majority of other European countries, empirical research on large samples of various Slovenian youth populations in 1993, 1995, 1999 and 2000 has disclosed young people's marked preferential interest in the private and the personal spheres of life, whereas their interest in politics is slight, as is the degree of trust in existing political institutions and actors. In Slovenia this trend is usually characterized as a ‘shift towards privacy’, and being apolitical is one of the most frequently invoked defining features of the younger generation.In the author's opinion, these research findings reveal huge changes in Slovenia's political space–paradoxically, this space has contracted in comparison to the situation in the 1980s, largely due to a narrower understanding of politics and political activity.

Microsatellite data resolve phylogeographic patterns in European grayling, Thymallus thymallus, Salmonidae.

The phylogeography of an endangered salmonid, European grayling (Thymallus thymallus), was studied based on analysis of 17 nuclear microsatellite DNA loci. In agreement with earlier mitochondrial DNA (mtDNA) studies, phylogenetic relationships of the populations suggested that northern Europe was colonized from two distinct Pleistocene refugia. Furthermore, microsatellites revealed highly supported grouping of mainland Swedish, Norwegian, Danish, German and Slovenian populations, suggesting that grayling from the northwestern and central Europe have descended from their southern conspecifics. The level of divergence between populations was substantial, even across short geographical distances. Although this was in part due to postglacial colonization patterns and contemporary barriers for gene flow, the high divergence estimates between hydrologically connected sampling locations implied efficient interpopulation reproductive isolation. Microsatellites revealed that the populations exhibited, on average, only 3.5 (+/-2.2) alleles per locus, indicating that T. thymallus has strikingly low levels of intrapopulation genetic diversity as compared with other freshwater fish species. Accordingly, as indicated by analysis of molecular variance (AMOVA), only 49.1-58.0% of the total grayling microsatellite diversity resided within populations. A latitudinal genetic diversity gradient, potentially resulting from glaciation-mediated founder events, was not evident. Alternatively, it is possible that grayling display limited dispersal behaviour/capability, leading to low long-term effective population sizes and, consequently, depauperate intrapopulation polymorphism. These findings have implications for conservation of T. thymallus. Importantly, they exemplify that microsatellites can be highly informative for intraspecific phylogeography studies dealing with substantial divergence scales.

Variation in eggshell characteristics and in intrauterine egg retention between two oviparous clades of the lizard Lacerta vivipara: insight into the oviparity-viviparity continuum in squamates.

The concept of the oviparity-viviparity continuum refers to the wide range in the length of intrauterine egg retention and, hence, in the stage of embryonic development at oviposition existing in squamates. The evolutionary process underlying this continuum may involve not only a lengthening of egg retention in utero, but also a marked reduction in the thickness of the eggshell. The idea that there may exist a negative correlation between the developmental stage reached by the embryo at oviposition and the eggshell thickness within squamates, although supported by the comparison of oviparous vs. viviparous species, has seldom been evaluated by comparing eggshell thickness of oviparous forms with different lengths of intrauterine egg retention. Eggs of two distinct oviparous clades of the lizard Lacerta vivipara were compared. The eggs laid by females from Slovenian and Italian populations have thicker eggshells, contain embryos on average less developed at the time of oviposition, and require a longer incubation period before hatching than the eggs laid by females from French oviparous populations. Our data and several other examples available from the literature support the idea that the lengthening of intrauterine retention of eggs and the shortening of the subsequent external incubation of eggs are associated with reduction in the thickness of the eggshell, at least in some lineages of oviparous squamates. The current hypotheses that may account for this correlation are presented and a few restrictions and refinements to those hypotheses are discussed. In particular, other changes, such as increased vascularization of the oviduct and of the extraembryonic membranes, may play the same role as the decrease of eggshell thickness in facilitating prolonged intrauterine egg retention in squamates. Future studies should also consider the hypothesis that the length of intrauterine retention might directly depend on the extent of maternal-fetal chemical communication through the eggshell barrier.

Phylogeography and conservation of the populations of Zootoca vivipara carniolica

The lizard Zootoca vivipara has both oviparous and viviparous populations which belong to distinct clades. This study aims to elucidate the geographic distribution, phylogeography and conservation priority of the oviparous subspecies, Zootoca vivipara carniolica, that has recently been identified in Slovenia. We studied seven Slovenian populations, two northeastern Italian populations and five northwestern Italian populations. The seven cytochrome b haplotypes that we identified from the Slovenian and Italian oviparous populations form a monophyletic basal clade. The high homogeneity of the Slovenian and northeastern Italian populations (nucleotide diversity π=0.06%) is a striking contrast with the pattern observed in northwest Italy where each of the five populations studied presents a private haplotype (π=1.03%). The results obtained suggest that all the extant lineages of Z. v. carniolica have originated in an Italian refuge. The reproductive and phylogenetic distinctiveness of Z. v. carniolica clearly justifies conservation of its populations, especially in Italy where the highest genetic diversity and the most ancestral haplotype were observed.

Evolutionary and biogeographical implications of the karyological variations in the oviparous and viviparous forms of the lizard Lacerta (Zootoca) vivipara

The lizard Lacerta (Zootoca)vivipara has two modes of reproduction and is variable karyologically. We describe its karyological variation from literature data and from new data on two viviparous populations from France, on two oviparous populations from the Pyrenees in south-western France and on three oviparous populations recently discovered in Slovenia. Males have 36 chromosomes, whereas females have only 35 chromosomes in all viviparous populations and in the Pyrenean oviparous populations. This karyotype has been interpreted to result from a fusion of an ancestral sexual W chromosome with an autosome from the Zl or from the Z2 pair. The karyotype formula is 32 autosomes + ZIZ2W for the female and 32 autosomes + Z1Z1Z2Z2 for the male. The karyotype of the Slovenian oviparous populations, 34 autosomes + ZW in the male and 34 autosomes +ZW in the female, represents an evolutionary stage that preceded the chromosomal fusion. There is minor karyological variation, mainly concerning the W and Z2 chromosomes, within the Pyrenean oviparous populations. This parallels the geographic variation of the W-linked alleles of the MPI enzyme and suggests that allopatric differentiation of these oviparous populations might have occurred in the vicinity of the Pyrenees during the Pleistocene. The viviparous populations from western Europe carry a metacentric W chromosome, whereas oviparous populations from south-western Europe and eastern viviparous populations both show an acrocentrie, or a subtelocentrie. W chromosome. This suggests that the acrocentric-subtelocentric W is a primitive character and that viviparity probably arose in an eastern lineage of the species.

Evolutionary and biogeographical implications of the karyological variations in the oviparous and viviparous forms of the lizard Lacerta (Zootoca) vivipara

The lizard Lacerta (Zootoca) vivipara has two modes of reproduction and is variable karyologically. We describe its karyological variation from literature data and from new data on two viviparous populations from France, on two oviparous populations from the Pyrénées in south‐western France and on three oviparous populations recently discovered in Slovenia. Males have 36 chromosomes, whereas females have only 35 chromosomes in all viviparous populations and in the Pyrenean oviparous populations. This karyotype has been interpreted to result from a fusion of an ancestral sexual W chromosome with an autosome from the Z1 or from the Z2 pair. The karyotype formula is 32 autosomes +Z1Z2W for the female and 32 autosomes+Z1Z1Z2Z2 for the male. The karyotype of the Slovenian oviparous populations, 34 autosomes +ZZ in the male and 34 autosomes +ZW in the female, represents an evolutionary stage that preceded the chromosomal fusion. There is minor karyological variation, mainly concerning the W and Z2 chromosomes, within the Pyrenean oviparous populations. This parallels the geographic variation of the W‐linked alleles of the MPI enzyme and suggests that allopatric differentiation of these oviparous populations might have occurred in the vicinity of the Pyrénées during the Pleistocene. The viviparous populations from western Europe carry a metacentric W chromosome, whereas oviparous populations from south‐western Europe and eastern viviparous populations both show an acrocentric, or a subtelocentric, W chromosome. This suggests that the acrocentric‐subtelocentric W is a primitive character and that viviparity probably arose in an eastern lineage of the species.

Intraspecific Phylogeography of Lacerta vivipara and the Evolution of Viviparity

The lacertid lizard Lacerta vivipara is one of the few squamate species with two reproductive modes. We present the intraspecific phylogeny obtained from neighbor-joining and maximum-parsimony analyses of the mtDNA cytochrome b sequences for 15 individuals from Slovenian oviparous populations, 34 individuals from western oviparous populations of southern France and northern Spain, 92 specimens from European and Russian viviparous populations, and 3 specimens of the viviparous subspecies L. v. pannonica. The phylogeny indicates that the evolutionary transition from oviparity to viviparity probably occurred once in L. vivipara. The western oviparous group from Spain and southern France is phylogenetically most closely related to the viviparous clade. However, the biarmed W chromosome characterizing the western viviparous populations is an apomorphic character, whereas the uniarmed W chromosome, existing both in the western oviparous populations and in the geographically distant eastern viviparous populations, is a plesiomorphic character. This suggests an eastern origin of viviparity. Various estimates suggest that the oviparous and viviparous clades of L. vivipara split during the Pleistocene. Our results are discussed in the framework of general evolutionary models: the concept of an oviparity–viviparity continuum in squamates, the cold climate model of selection for viviparity in squamates, and the contraction–expansion of ranges in the Pleistocene resulting in allopatric differentiation.

Vibratory songs of hybrids from Brazilian and Slovenian populations of the green stink bug Nezara viridula

Vibratory songs of hybrids from Brazilian and Slovenian populations of the green stink bug Nezara viridula

Vibratory songs of hybrids from Brazilian and Slovenian populations of the green stink bug Nezara viridula

Males and females of the green stink bug Nezara viridula produce species and sex specific vibrational signals. The songs of bugs from geographically isolated population differ in their temporal characteristics. Hybrids were produced between the bugs from Brazilian and Slovenian populations in order to examine the levels of genetic inheritance of their vibratory songs. Hybrid males and females produced songs which are distinctly different from parental songs and these differences can be attributable to genetic factor. The results show that in some parameters the hybrid songs are intermediate between the parental types. Several song parameters are apparently sex-linked. It remains to be established whether observed genetically determined differences in vibratory songs also indicate that cryptic species exist within the taxon N. viridula.

Vibrational communication in Nezara viridula: response of Slovenian and Australian bugs to one another

Temporal patterns of intersexual vibrational communication between Slovenian and Australian populations of Nezara viridula were investigated. The vibrational and mating responses of individuals of each sex to individuals of the opposite sex from the alternative population were recorded during mating experiments. Australian females did not respond to Slovenian males and only a few copulations occurred in this direction, whereas Slovenian females and Australian males responded to each other and copulated regularly. The two populations probably represent distinct sibling species, but this needs to be clarified further. Whether the observed mating asymmetry actually occurs regularly in nature, also warrants investigation. We suggest how these issues may be resolved.

ASELLUS AQUATICUSINFERNUS, NEW SUBSPECIES (ISOPODA: ASELLOTA: ASELLIDAE), FROM ROMANIAN HYPOGEAN WATERS

A new, troglomorphic subspecies of Asellus aquaticus, A. a. infernus, from Romania, is described and illustrated. The general architecture of the copulatory appendages, studied with SEM in Romanian and Slovenian hypogean and epigean populations, is compared and discussed. A difference in brood size was determined between Romanian hypogean and epigean populations. Extensive analysis of the data using multivariate discriminant function analysis (DFA) allowed the elucidation of racial differentiation patterns in A. aquaticus from Romania and Slovenia. The number of the initially measured morphometric characters was greatly reduced as the contribution of each character to each discriminant function was assessed. DFA divided the sample complex into distinct epigean-A. a. aquaticus, and hypogean forms-A. a. infernus (Romania) and A. a. cavernicolus (Slovenia). The size of pleopod V and its area as well as the isometric (short distal rami) uropod represent the most important discriminant characters. Distinct separation of Romanian and Slovenian cave populations, i.e., the low degree of convergent evolution toward troglomorphism, might be at least to some extent explained by a different origin of populations and by the considerable ecological differences between both habitats. Asellus (Asellus) aquaticus (L., 1758) is an extreme eurytopic, eurythermal, and expansive species, represented not only in surface waters, but also in all types of hypogean fresh-water systems (Henry et al., 1996). In many localities all over Europe, populations with more or less depigmented specimens are present. However, only some races from Slovenia (Sket, 1965) and Romania (Negoescu, 1989) show further adaptive changes: reduced body pigmentation and depigmented or even degenerated eyes (Sket, 1994; Turk

Population-specific behavioral electrosensitivity of the European blind cave salamander, Proteus anguinus

In nine salamanders from different Slovenian populations of the urodele Proteus anguinus, including three specimens of its ‘black’ variety, P anguinus parkelj, thresholds of an overt avoidance response to electrical field stimuli were estimated as a function of frequency (continuous sine-waves in water). Thresholds down to 0.3 mV/cm ( ca 100 nA/cm 2) and up to 2 mV/cm (670 nA/cm 2), at ‘best frequencies’ of around 30 Hz were found. Sensitivity covered a total frequency range of below 1 Hz, excluding DC, up to 1–2 kHz with up to 40 dB higher thresholds. Thresholds and tuning curves are compared with those of a Proteus population raised in captivity for more than 35 years. The biological significance and the apparently still ongoing evolution of the electrical sense in urodeles, ie in the genus Proteus, are interpreted in terms of comparative sensory physiology and ethological ecology as a result of more recent evolutionary diversification during and since glaciation in the Pleistocene.

A black, non-troglomorphic amphibian from the karst of Slovenia: Proteus anguinus parkelj n. ssp. (Urodela: Proteidae)

A morphologically distinct cavernicolous salamander Proteus anguinus from southeastern Slovenia (Bela Krajina) is described as P. a. parkelj ssp. n. It differs from P. a. anguinus in a dark pigmentation, fully developed eyes, a skull with broader and shorter bones and fewer teeth, a voluminous jaw musculature that gives the head a bulky appearance, a proportionally longer trunk with a higher number of vertebrae, shorter extremities, and a shorter tail. Most of these traits are considered to be plesiomorphic character states. An allozyme analysis over 40 loci has shown the new dark pigmented taxon to be genetically similar to a white and troglomorphic neighbouring population from Stična (DNei = 0.23). Both populations in turn are genetically dissimilar to a geographically more distant population from Postojna (D Nei = 0.49). The observed level of genetic differentiation suggests that western and southeastern Slovenian populations form separate lineages since the uppermost Miocene but conservatively hitherto only a single species is recognised. The new taxon is only known from a small area and may be rare. P. a. parkelj, now under strict legal protection, is threatened by industrial pollution.