Swiss Populations Research Articles

Spatial structure and clonal distribution of genotypes in the rare Typha minima Hoppe (Typhaceae) along a river system

We studied the genetic diversity of the dwarf bulrush (Typha minima) along a 60 km section of the Isere river using AFLP markers. Total clonality was relatively low (proportion of distinguishable genotypes = 0.70) but extremely variable among populations with one monoclonal population and several populations where all sampled individuals were different. Genetic diversity was high (He = 0.129) and again variable among populations. Although no major genetic discontinuity could be detected, gene flow was found to be limited. Our results show a much higher diversity compared to Swiss populations. The high genetic diversity within most populations despite the species’ potentially important clonal growth indicates that populations are relatively young. This is in line with the fact that the species lives in open habitats created by high floods that erase river banks leading to a metapopulation dynamics. However the metapopulation dynamics is at least partly disturbed as gene flow appears to be restricted so that our populations are probably at risk if no action is taken to re-establish more natural river flow dynamics.

A review of the natural history and laboratory culture methods for the yellow dung fly, Scathophaga stercoraria.

The yellow dung fly Scathophaga stercoraria (L.) (Diptera: Scathophagidae) is a widespread and locally abundant fly associated with the dung of large mammals, especially farm animals. This species has recently become a standard test organism for evaluating toxic effects of veterinary pharmaceuticals in livestock dung. In this context, a review of its natural history and a general description of the field and laboratory rearing methods of this species are provided here to benefit the scientific community as well as government regulators and applicants of eco-toxicological studies. For guidance, means and ranges are included for all relevant standard life history traits stemming from previously published data on Swiss populations.

Assessment of dental fluorosis prevalence in Swiss populations.

In 1996 and 2006, recruits of the Swiss army participated in a dental survey. Similarly in 1995/96 and 2004/05, randomly selected schoolchildren from 16 rural communities of the Canton of Zurich participated in a dental survey. As part of these surveys, color slides were taken of the incisor teeth of all recruits, as well as of third and fourth grade schoolchildren. The slides (N = 2049) were examined for the presence of fluoride-associated enamel opacities (FOP), using the Thyl-strup-Fejerskov (TF) index. Two examiners (A and B) assessed all slides. The examiners were blind as to the year of survey. Examiner A recorded prevalences of FOP between 18% and 27% depending on population; examiner B recorded prevalences between 7% and 12%. The examiners' influence on the estimation of the prevalence was obvious. The prevalences reported should, therefore, be considered as rough estimates. FOP of TF score 2 were only observed in approximately 1% of the participants. One examiner recorded a TF score 3 in a single individual. FOP therefore are not a cosmetic problem and certainly not a public health concern. The prevalence of FOP decreased slightly during observation period I (recruits born 1975-77 vs 1985-87) and period II (school children born 1985-87 vs 1994-96). However, the decline was statistically supported in only one instance (Period I, Examiner B).

A strong genetic footprint of the re‐introduction history of Alpine ibex (Capra ibex ibex)

A population's neutral genetic variation is a composite of its size, degree of isolation and demographic history. Bottlenecks and founder events increase genetic drift, leading to the loss of genetic variation and increased genetic differentiation among populations. Gene flow has the opposite effects. Thus, gene flow can override the genetic patterns caused by founder events. Using 37 microsatellite loci, we investigated the effects of serial bottlenecks on genetic variation and differentiation among 42 Alpine ibex populations in Switzerland with known re-introduction histories. We detected a strong footprint of re-introduction events on contemporary genetic structure, with re-introduction history explaining a substantial part of the genetic differentiation among populations. As a result of the translocation of a considerable number of individuals from the sole formerly surviving population in northern Italy, most of the genetic variation of the ancestral population is now present in the combined re-introduced Swiss populations. However, re-introductions split up the genetic variation among populations, such that each contemporary Swiss population showed lower genetic variation than the ancestral population. As expected, serial bottlenecks had different effects on the expected heterozygosity (He) and standardized number of alleles (sNa). While loss of sNa was higher in the first bottlenecks than in subsequent ones, He declined to a similar degree with each bottleneck. Thus, genetic drift was detected with each bottleneck, even when no loss of sNa was observed. Overall, more than a hundred years after the beginning of this successful re-introduction programme, re-introduction history was the main determinant of today's genetic structure.

Geographic patterns of genetic differentiation and plumage colour variation are different in the pied flycatcher (Ficedula hypoleuca)

The pied flycatcher is one of the most phenotypically variable bird species in Europe. The geographic variation in phenotypes has often been attributed to spatial variation in selection regimes that is associated with the presence or absence of the congeneric collared flycatcher. Spatial variation in phenotypes could however also be generated by spatially restricted gene flow and genetic drift. We examined the genetic population structure of pied flycatchers across the breeding range and applied the phenotypic Q(ST) (P(ST))-F(ST) approach to detect indirect signals of divergent selection on dorsal plumage colouration in pied flycatcher males. Allelic frequencies at neutral markers were found to significantly differ among populations breeding in central and southern Europe whereas northerly breeding pied flycatchers were found to be one apparently panmictic group of individuals. Pairwise differences between phenotypic (P(ST)) and neutral genetic distances (F(ST)) were positively correlated after removing the most differentiated Spanish and Swiss populations from the analysis, suggesting that genetic drift may have contributed to the observed phenotypic differentiation in some parts of the pied flycatcher breeding range. Differentiation in dorsal plumage colouration however greatly exceeded that observed at neutral genetic markers, which indicates that the observed pattern of phenotypic differentiation is unlikely to be solely maintained by restricted gene flow and genetic drift.

Detection of testosterone administration based on the carbon isotope ratio profiling of endogenous steroids: international reference populations of professional soccer players

Background and objectives:The determination of the carbon isotope ratio in androgen metabolites has been previously shown to be a reliable, direct method to detect testosterone misuse in the context of...

Morphology, Biometry, and Taxonomy of Freshwater and Marine Interstitial Cyphoderia (Cercozoa: Euglyphida)

Good taxonomy is essential for ecological, biogeographical, and evolutionary studies of any group of organisms. Therefore, we performed detailed light- and scanning electron microscopy investigations on the shell ultrastructure and biometric analyses of the morphometric variability of five freshwater and marine interstitial testate amoebae of the genus Cyphoderia (C. trochus var. amphoralis, C. ampulla, C. margaritacea var. major, C. compressa, and C. littoralis), isolated from different populations in Bulgaria and Switzerland. Our aims were (1) to clarify the morphological characteristics of these taxa, and (2) to compare the morphology of a given taxon (C. ampulla) among different locations in Bulgaria and Switzerland as a first step towards an assessment of the geographical variation within a supposedly cosmopolitan taxon. Four of the studied taxa are characterized by a well-expressed main-size class and by a small size range of all the characters and can be defined as size-monomorphic species. Based on these results, the following systematic changes are proposed: C. major (Penard, 1891) n. comb. (Syn.: C. margaritacea var. major (Penard, 1891) and C. amphoralis (Wailes & Penard, 1911) n. comb. (Syn.: C. trochus var. amphoralis (Wailes & Penard, 1911)). However, we also show significant morphological variability between the Swiss and Bulgarian populations of C. ampulla, suggesting the possible existence of more than one taxon within this species. Further studies are required to assess (1) if these two morphologically different taxa represent individual species, (2) if so, if more species exist, and if this diversity is due to limited distribution ranges (endemism) or if several closely related taxa occur together in different geographical areas.

Bursa Bölgesinde Yetiştirilen İsviçre Esmeri ve Siyah Alaca Irkı Sığırlarda Beta Laktoglobulin (β-lg) ve Büyüme Hormonu (bGH) Gen Polimorfizmlerinin HaeIII ve MspI Restriksiyon Enzimleri Kullanılarak İncelenmesi

Summary In this study polymorphism on β-lg and bGH genes in Holstein and Brown Swiss cattle reared in Bursa region were investigated by using HaeIII and MspI restriction enzymes. While frequencies of A and B allelles of β-lg were found 0.3430 and 0.6570 in Brown Swiss population, they were found as 0.5480 and 0.4520 in Holstein population, respectively. MspI (+) allelle of bGH was predominat in both Brown Swiss and Holstein populations with frequency of 0.9623 and 0.8158, respectively. Both of two populations were found in Hardy- Weinberg equilibrium for both of the two loci investigated.

LRRK2 mutations are not frequent in Swiss patients with Parkinson's disease

A wealth of recent data has shed light on the genetics of Parkinson's disease. Mutations of specific genes have been discovered in a number of autosomal dominant and recessive forms of the disease, and polymorphisms in the same or other genes found to be associated with its occurrence in sporadic forms. Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) cause an autosomal dominant form of Parkinson's disease (PARK8) and have been found in patients with Parkinson's disease with a highly variable frequency in different populations in the world. In this study we have examined the most common mutations so far described in this large gene: p.R1441C (together with p.R1441G and p.R1441H), p.Y1699C and p.G2019S. Seventy-three patients from Switzerland with Parkinson's disease diagnosed according to Brain Bank criteria with the exception of positive family history were included in this study. The three exons, in which the above mutations had been found, were sequenced after amplification. There were no sequence differences compared with the published wild-type sequences in all patients. These data point at the low incidence of LRRK2 mutation in the Swiss (regions of Berne and Zurich) populations, similar to findings in other central European populations, but at great variance to Mediterranean populations.

First Report of Root-Knot Nematode Meloidogyne enterolobii on Tomato and Cucumber in Switzerland.

Severe stunting and extensive root galling were observed on tomato rootstock (Solanum lycopersicum L. cv. Maxifort) resistant to Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949, M. javanica (Treub, 1885), and M. arenaria (Neal, 1889) Chitwood, 1949 and cucumber (Cucumis sativus L. cv. Loustik) from two commercial greenhouses in the cantons Aargau and Lucerne in northern Switzerland. Examination of the roots of infected plants revealed the presence of root-knot nematodes in large numbers. Juveniles, males, and females were isolated, and the species was determined on the basis of morphological characteristics, including the female perineal pattern. Identification was confirmed by female esterase (Est) and malate dehydrogenase (MdH) electrophoresis (20 each for Est and MdH). All methods of identification were consistent with M. enterolobii Yang & Eisenback, 1983 (4). For further confirmation, type material of M. enterolobii (from the original host Enterolobium contortisiliquum (Vell.) Morong) from China (4) was used. Furthermore, comparison of the sequence data from 12 individuals of each of the two Swiss populations and the type material of a 310-bp fragment of cytochrome oxidase I (COI), a 723-bp fragment covering the internal transcribed spacer (ITS) region 1, 5.8s, ITS2, and part of the 26s, the mtDNA 63-bp repeat region, and a 780-bp fragment of the intergenic spacer region (1-3) showed 100% homology and confirmed the identification as M. enterolobii. The species M. enterolobii is of great importance because it is able to reproduce on resistant tobacco, pepper, watermelon, and tomato (4). To our knowledge, this is the first report of M. enterolobii in Switzerland.

Populationsgeschichte und Managementprinzipien in Schweizer Wildbirnenvorkommen | Population history and management principles in Swiss Wild Pear populations

Genetic studies show that genetic diversity is positively correlated with population size: however, this correlation has not been found in Swiss populations of Wild Pear. The present investigation implies that the diverse historical human uses of Wild Pear populations offer an explanation for this lack of correlation. Current populations of Wild Pear are located in sparse and structured forests, often characterized by a meadow-like herb layer. For the conservation and augmentation of the mostly small Wild Pear populations, the principle of dominance reduction can be applied. It leads to a variety of light conditions within woodlands and imitates the currently abandoned historical forest uses.

Patterns of variation of a common fern (Athyrium filix‐femina; Woodsiaceae): population structure along and between altitudinal gradients

Genetic variability of Athyrium filix-femina populations was evaluated with regard to phenotypic, allozyme, and RAPD variation in 20 Swiss populations along five altitudinal gradients at four different elevations in the northern Swiss Alps. Additionally, allozyme and phenotypic variations in one Italian and two Spanish populations were compared with the variation in the Swiss populations. We hypothesized that there will be statistically significant genetic differences among populations of different altitudes and sites. The results showed no substantial correlation between genetic variation and phenotypic variation among Swiss populations. These results imply that outbreeding and effective gene exchange (long-distance spore dispersal) are the keys to population structure in this fern species, and as a consequence, phenotypic plasticity is assumed to be favored. This contrasts with results found in similar studies of herbaceous flowering plants where genetic adaptation to gradients like altitude is common. However, when data from the more distant Italian and Spanish populations of A. filix-femina were included, significant variation was detected.

Regional population dynamics define the local genetic structure in Sorbus torminalis

Recent changes in sylvicultural practices in Central Europe have created forests with closed canopies, and tree species preferring open and sunny forests have declined in area and abundance. This led to increased isolation of populations of many rare insect-pollinated, fleshy-fruited species with a naturally scattered distribution. To gain insight into the regional population dynamics of such species, we investigated the consequences of spatial isolation, population size and density on the genetic structure of Sorbus torminalis and simultaneously considered the relationship between fecundity and habitat quality. Genotype data for biparentally (ISSRs) and maternally inherited (cpDNA PCR-RFLPs) molecular markers were generated for 26 Swiss populations of S. torminalis. We applied analyses of molecular variance (amova) to both marker types and separated the relative contributions of pollen and seed dispersal to historical gene flow. amova detected significant differentiation among populations (Phi(ST ISSR) = 0.107; Phi(ST cpDNA) = 0.370) in both marker types. The relative rate of pollen to seed gene flow was low (r = 2.919) and significantly different from equality. Isolation by distance was weak within Eastern and Western Switzerland, although populations were substantially differentiated. Within-population molecular variance was not explained by population size, whereas habitat quality (openness) positively influenced the percentage of fruiting trees and the degree of fruiting per tree, indicating that more open forests enhance sexual reproduction. Our findings of significant genetic differentiation in the absence of clear geographical structuring can be explained by the distinct ecology of S. torminalis and nondirectional colonization events in metapopulation-like dynamics.

The QuaLAT project: mapping QTL for milk fatty acid content in the Italian Brown population and in the Israel Holstein Friesian

Milk contains a number of micro-components (“functional foods”) having specific health promoting activities. Important among these compounds are the conjugated linoleic acids (CLAs) consistingof a mixture of isomers of C18:2 fatty acid with conjugated doublebonds. The predominant form in milk fat is the cis-9,trans-11 isomer, accounting for 75 to 90% of the total CLA content. Biomedical studies with animal models have demonstrated a variety of preventive health effects from CLA including anticarcinogenic, antiatherogenic, antiobesity, immune system enhancement and antidiabetic benefits. Linolenic acid does not form CLA as an intermediate in rumen biohydrogenation, but it does form vaccenic acid (C18:1,t11) that enters the bloodstream from the rumen, through the abomasum and intestine, and is transported to the mammary gland. Several investigations using direct and indirect approaches established that endogenous synthesis of CLA via ∆9-desaturase action on vaccenic acid (VA, C18:1,t11) is the predominant source of the CLA found in milk fat across a range of diets. Thus, rumen VA production and mammary tissue ∆9-desaturase (D9D) are of key importance in determining the CLA content of milk fat. Mammary tissue D9D activity is measured indirectly as the milk desaturase index (DI), calculated as the ratio of milk CLA to the sum of milk CLA and VA. The study is centered on the Italian Brown Swiss and Israeli Holstein dairy cattle populations. Objectives of the project are: i) to identify environmental and physiological factors (e.g., herd, season, parity and stage of lactation) affecting milk CLA content and DI, and determine appropriate correction factors, if needed; ii) to estimate heritability of milk CLA content and DI in the study populations; iii) to implement a total genome scan for QTL affecting milk CLA VA content and DI in the two study populations. using a selective DNA pooling approach based on milk samples for the initial scan, followed by individual genotyping to confirm suggestive QTL regions. For each of the studied populations,, the research includes determination of CLA, VA and DI for more than 2500 individuals of five large sire half-sib families (for the genome scan) and an additional 400 individuals of 20 small sire half-sib families for the heritability analysis. Milk fat is extracted and transmethylated according to Chouinard et al. (1999). Fatty acid methyl esters are analyzed by GC-FID with a highly polar 100 m SP-2560 column, using GLC-60 supplemented with CLA and VA as a standard. Based on the results obtained to date for the Italian Brown Swiss population, the mean (fatty acid composition over the total fatty acid) ±SD( minimum and maximum) are respectively: VA, 1.97±0.77 (0.63 - 5.40); CLA, 0.63±.0.47 (0.35 - 5.31); DI, 0.25±0.097 (0.063 - 0.64). The means for VA and CLA content found are similar to those reported by other studies (control treatment) and reviewed by Collomb et al (2006). The slightly larger variability here reported, anyhow within the limit of values found in literature, is possibly affected by the wide farming conditions of the individuals sampled.

Immigration Policies, State Discourses on Foreigners, and the Politics of Identity in Switzerland

The role of state discourses in the construction of ‘otherness’ and in the production of inequality has become a major issue during a time of increasing changes in migration flows, of an increased presence of nationalist parties, and of increasingly restrictive immigration policies in Europe. In this paper we examine historical shifts in the representation of foreigners within Swiss state discourses and the effects of these shifts on the integration of immigrants into Swiss society. As state discourses regarding foreigners significantly changed after the First World War, the emphasis of immigration policies shifted from a facilitating to a constraining approach. Überfremdung, the notion that excessive numbers of foreigners can threaten Swiss identity, emerged as one of the most influential discourses in Switzerland and provided the foundation for a quantitative and qualitative strategy of defence against the immigration, settlement, and naturalisation of foreigners. In recent years, however, an agreement on freedom of movement between Switzerland and the European Union has been struck, and immigration policies have once again adopted a facilitating stance. As this applies only to citizens of the European Union, a stratified system of immigrant rights has been continued and perpetuated. At the same time, right-wing parties, which have recently risen to power, have successfully used Überfremdung propaganda to persuade Swiss populations to vote against the relaxation of conditions for the naturalisation of foreigners, thus ensuring that immigrants will be excluded from access to citizenship rights over generations. The politics of immigration in Switzerland is above all a politics of national identity.

HER2, TOP2A, CCND1, EGFR and C-MYC oncogene amplification in colorectal cancer

Aim: Recent studies had suggested substantial molecular differences between tumours from different ethnic groups. In this study, the molecular differences between the incidences of colorectal carcinoma in Saudi and Swiss...

The RHCE allele ceSL: the second example for D antigen expression without D‐specific amino acids

The example of ceRT proved that the expression of some D epitopes does not require D-specific amino acids. This allele denoted as RHce(R154T) caused the "false-positive" reactions that were observed in ccddee blood donors who typed positive for the D antigen with some monoclonal anti-D. No other example exposing a similar molecular mechanism was known. Eleven donor and 1 patient ccddee samples were collected in Switzerland that typed "false-positive" with some monoclonal anti-D in bromelain technique. Their RHCE alleles were determined by nucleotide sequencing from genomic DNA and by a polymerase chain reaction with sequence-specific priming. The D epitope profile was compared to ceRT. The population frequencies were estimated in Switzerland and Germany by serology or at the molecular level, respectively. The "false-positive" reactions were caused by the RHCE allele RHce(S122L) occurring in the cde haplotype. Its ceSL phenotype expressed few D epitopes that belonged to the D epitope 6 group. The frequency of ceSL among D- donors was about 1:675 in the region of Bern, Switzerland. No ceSL donors were found elsewhere in Switzerland or in southwestern Germany. ceSL represented the second molecular mechanism for D antigen expression without any D-specific amino acids. ceSL and ceRT were useful to delineate the molecular mechanisms of D expression by RhCE proteins carrying amino acids not representative for the RhD proteins. The ceSL population frequencies differed significantly among three Swiss and German populations.

Cadmium tolerance and hyperaccumulation by Thlaspi caerulescens populations grown in hydroponics are related to plant uptake characteristics in the field.

In order to fully understand the hyperaccumulation process and to increase the potential of plants for phytoextraction purposes, there is a need for more investigation of hyperaccumulating species or populations. Five Swiss populations of Thlaspi caerulescens J. & C. Presl originating from non-metalliferous but naturally Cd-rich soils (1.1-9.2 mg Cd kg-1) were compared with Ganges and Prayon populations and a non-accumulating species, Thlaspi perfoliatum (L.) F.K. Meyer, for their tolerance (shoot and root dry weight and root length) and Cd hyperaccumulation in hydroponics (0, 1, 5, 10, 20 and 50 μm Cd). In the field, the Swiss populations accumulated Zn and clearly hyperaccumulated Cd (up to 505 mg Cd kg-1 dry weight). The general response was significantly different between populations but in general an increasing Cd concentration in solution led to a decrease in dry weight production and an increase in Cd concentration in shoots. The shoot dry weight was a more discriminating parameter for tolerance than root dry weight and total root length. The Swiss populations behaved similarly to the Ganges population but differently from the Prayon population. Cadmium concentrations in shoots were above 100 mg kg-1 when plants were grown in 1 μm Cd, except for the Prayon population and T. perfoliatum. In addition, as 1 μm Cd did not induce any visible toxicity symptoms, it was found to be adequate to test Cd hyperaccumulation. However, the most striking feature was the positive linear relationship observed between the transfer factor (TF) calculated in the field and the response of a population to increasing Cd concentrations in solution, indicating that plant uptake in the field had an influence on the plant response in solution.

Microsatellites reveal regional population differentiation and isolation inLobaria pulmonaria, an epiphytic lichen

Many lichen species produce both sexual and asexual propagules, but, aside from being minute, these diaspores lack special adaptations for long-distance dispersal. So far, molecular studies have not directly addressed isolation and genetic differentiation of lichen populations, both being affected by gene flow, at a regional scale. We used six mycobiont-specific microsatellite loci to investigate the population genetic structure of the epiphytic lichen Lobaria pulmonaria in two regions that strongly differed with respect to anthropogenic impact. In British Columbia, L. pulmonaria grows in continuous old-growth forests, while its populations in the old cultural landscape of Switzerland are comparably small and fragmented. Populations from both British Columbia and Switzerland were genetically diverse at the loci. Geographically restricted alleles, low historical gene flow, and analyses of genetic distance (upgma tree) and of differentiation (amova) indicated that populations from Vancouver Island and from the Canadian mainland were separated from each other, except for one, geographically intermediate population. This differentiation was attributed to different glacial and postglacial histories of coastal and inland populations in British Columbia. In contrast to expectations, the three investigated Swiss populations were genetically neither isolated nor differentiated from each other despite the long-lasting negative human impact on the lichen's range size in Central Europe. We propose that detailed studies integrating local landscape and regional scales are now needed to understand the processes of dispersal and gene flow in lichens.

Intra-specific variability of ozone sensitivity in Centaurea jacea L., a potential bioindicator for elevated ozone concentrations

Brown knapweed ( Centaurea jacea L.) has been suggested as a potential bioindicator for tropospheric ozone (O 3), but little is known about the intra-specific variation in O 3 sensitivity in this wild species. The aim of this study was to quantify the differences in O 3 sensitivity among and within five populations, and to relate the differences to morphological, phenological, and genetic characteristics. These parameters were periodically recorded in two consecutive experiments on a total of 357 plants from five different European countries (Norway, Hungary, Switzerland, Italy, Slovenia). They were grown from seed in natural soil under ambient conditions at a site with seasonally elevated O 3 concentrations (Cadenazzo, southern Switzerland). The populations differed significantly both in frequency and extent of O 3 injury, as well as in phenological development. The observed degree of O 3 injury was highest in the Slovenian and the Swiss populations, while only few Hungarian and Norwegian plants showed slight symptoms of injury. Plants were generally most sensitive to O 3 when reaching the reproductive stage, and insensitive at the rosette stage. Amplified fragment length polymorphism analysis (AFLP) demonstrated genetic distinctiveness of the five C. jacea populations. All individuals of four of the five populations were correctly assigned to the respective populations based on principal component analysis. Cluster analysis quite accurately reflected the geographic origin of each population. Overall, the analysis revealed a high degree of intra-specific variability in O 3 sensitivity in C. jacea, and underlined the important influence of the climate-dependent population-specific plant development on O 3 sensitivity. These observations may constrain the development of a standardized biomonitoring system.