Phylogeography of the barbel (Barbus barbus) assessed by mitochondrial DNA variation

Using the phylogeographic framework, we assessed the DNA sequence variation at the mitochondrial cytochrome b gene across the distribution range of the barbel Barbus barbus, a widely distributed European cyprinid. Reciprocal monophyly of non-Mediterranean European and Balkan/Anatolian populations is taken as evidence for a long-term barrier to gene flow, and interpreted as a consequence of survival of the species in two separate refugia during several later glacial cycles. Lack of profound genealogical divergence across Europe from western France to the northwestern Black Sea basin is consistent with recent colonization of this area from a single glacial refuge, which was probably located in the Danube River basin. This may have occurred in two steps: into the Western European river basins during the last interglacial, and throughout the Central European river basins after the last glacial. The populations from the Balkans and Anatolia apparently did not contribute mitochondrial DNA to the post-Pleistocene colonization of non-Mediterranean Europe. Lack of detectable variation within the Balkans/Anatolia is attributed mainly to recent expansion throughout these regions, facilitated by the freshwater conditions and seashore regression in the Black Sea during the Late Pleistocene and Early Holocene.     

Complex patterns of colonization and refugia revealed for European grayling Thymallus thymallus,based on complete sequencing of the mitochondrial DNA control region

The complete mitochondrial DNA (mtDNA) control region (1043 base pairs) and 162-bp of flanking transfer RNA genes were sequenced in 316 European grayling, Thymallus thymallus, from 44 populations throughout the Western European range of the species. A total of 58 haplotypes were revealed with pairwise divergence ranging from 0.001 to 0.038. An inferred intraspecific phylogenetic tree revealed two well-supported clades within the Danube basin, one highly divergent clade in the Adriatic basin, and one large, diverse group representing most other populations. A deeply divergent haplotype fixed in the Loire basin in central France, more groups of haplotypes from distinct Danubian tributaries, and a relatively ancestral haplotype fixed in former tributaries of the Elbe in Denmark all suggest a complex pattern of interglacial and postglacial expansions originating from disjunct refugia throughout central Europe. Despite some evidence of human-mediated stock transfers, parsimony-network-based nested-clade analysis (NCA) supported specific inferences relating to corridors of postglacial expansion such as the lower Rhine (Moselle) and Elbe systems (Danish populations) serving as sources for expansion into the Baltic to the north as well as the upper Rhine and Danube to the south; and specific Rhine populations (Doller, Orbe and Reuss) serving as sources for colonization of the Rhone. The multiple divergent clades representing populations in the upper Danube, as well as the deeply divergent haplotypes found in the Adriatic and Loire basins (> 5% divergence from Asian outgroups) support the theory that European grayling have had a long history in Western Europe, pre-dating Pleistocene glacial cycles. The patterns of mtDNA divergence shown here support a perspective of rich inter- and intrabasin genetic diversity that should be protected from current trends to translocate brood stocks for rearing and release in response to declining populations, especially in southern European basins.     

Genetic subdivision and biogeography of the Danubian rheophilic barb Barbus petenyi inferred from phylogenetic analysis of mitochondrial DNA variation

The barb Barbus petenyi is a cyprinid widely distributed throughout the mountain regions in the Danube River basin. Phylogenetic analysis of the DNA sequence variation at the mitochondrial cytochrome b gene over much of this range yielded three deep-branching (5.9-9.4% average divergence), well-supported haplotype clades with mutually exclusive geographic distributions and divergence times estimated to be in the Tertiary. The clades did not form an altogether monophyletic group as the most divergent one coalesced more recently with haplotypes of phylogenetically close species than with the other B. petenyi haplotypes. This pattern was supported by bootstrap and log-likelihood Shimodaira-Hasegawa tests. The other two were sister clades, but their distinctiveness was supported by previous allozyme data. Hence, from a taxonomic point of view, the current recognition of B. petenyi is erroneous, as it does not represent a single evolutionary lineage, and we suggest that three species be recognized instead. Substantial phylogeographic differences were evident among the three putative species, the two more southerly ones displaying significant structure, which suggested that they each survived in several glacial refugia throughout the Pleistocene. The phylogeographic pattern of multiple populations of rheophilic barbs with a history of long-term persistence and separation within the Danube River basin is novel within fishes and provides a hypothesis against which phylogeographic patterns among other similarly distributed rheophilic species may be compared.     

Genetic diversity and phylogenetic origin of brown trout Salmo trutta populations in eastern Balkans

The study focuses on the phylogenetic origin and genetic diversity of brown trout in the eastern part of the Balkan Peninsula. It further aims to reveal the impact of human-mediated transfers and stocking with non-indigenous trout on the populations in this area. For these purposes, mtDNA control region and microsatellite variation of 204 individuals from 16 populations were analysed. The results indicate that mtDNA haplotypes from the lower Danube basin and southern Black Sea basins differ substantially from a subclade of the Danubian lineage consisting of haplotypes found so far in the most of the Danube basin and in the Caspian and Aral Sea basins. Considering also the results of demographic analyses, this study evidences a complex evolutionary history of brown trout in the southern and western parts of the Black Sea basin. In the Aegean Sea basin, a high frequency of the central haplotype of Adriatic mtDNA lineage has been found. The other Adriatic lineage haplotypes found in this basin differ from the central haplotype by one mutational step only, indicating a recent evolution of the Adriatic lineage in the Aegean Sea basin. Substantial genetic differentiation among populations and basins was revealed. The hybridization with Atlantic brown trout was indicated in both sea basins, but especially in the Danube basin. Compared to other European regions, it can be inferred that the introgression of exogenous brown trout in the eastern Balkan populations is rather low.     

The Alps as barrier to dispersal in cold-adapted freshwater fishes? Phylogeographic history and taxonomic status of the bullhead in the Adriatic freshwater drainage

The freshwater faunas of the Italian peninsula are isolated from the rest of Europe by the geographic barrier of the Alps and consequently have developed many endemic forms and contain few non-endemic species. However, some 'non-endemics' may either represent recent invaders of the Adriatic basin or cryptic endemic species. To test these two hypotheses against each other, we studied the origin and phylogenetic relationships of bullheads, cold adapted freshwater fishes of the genus Cottus, from both sides of the Alps and Dinaric Mountains. From the Adriatic basin, Cottus ferrugineus () was described as an endemic species, but the present analyses of sequences of the complete mitochondrial control region of 146 individuals from 43 localities showed no major differentiation between bullheads from both sides of the Alps. The very low diversification between representatives across the Alps suggests active transfers of haplotypes across this geographic barrier from the glacial cycles up to recent times. The transfers are most likely based on stream capture, since the cold-adapted bullhead is able to colonise the highest stretches of the water courses. No other freshwater fish in Europe is known to have experienced such an extensive gene flow across the highest European Mountains. In contrast, the Dinaric Mountains seem to have been a much more effective barrier between the Danube and the Adriatics. Our data reject the hypothesis of C. ferrugineus as an endemic species in the whole Adriatic drainage.     

Population genetic analysis of European Prunus spinosa (Rosaceae) using chloroplast DNA markers

Chloroplast DNA diversity in Prunus spinosa, a common shrub of European deciduous forests, was assessed using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique. Thirty-two haplotypes were detected in 25 populations spread across the European continent. Ten haplotypes were shared by two or more populations, and 22 were private. The major proportion of the total cpDNA diversity (H(T) = 0.73) was located within the populations (H(S) = 0.49), and differentiation between populations was low (G(ST) = 0.33) compared with other forest species. Haplotype diversity was higher in southern Europe than in northern Europe, indicating probable localization of glacial refugia in southern Europe. The minimum-length spanning tree of haplotypes showed incongruency between the phylogeny of haplotypes and their geographic locations. This might be the result of intensive seed movements following recolonization, which thereby erased the phylogeographic structure in P. spinosa.     

Phylogeography of the vairone (Leuciscus souffia,Risso 1826) in Central Europe

The vairone Leuciscus souffia is a cyprinid fish that inhabits river systems in and around the Alps. The complete mitochondrial DNA control region (945 bp) was sequenced in 295 vairone from 22 populations in Central Europe. A total of 51 haplotypes were identified with a maximum pairwise distance between haplotypes of 5.6%. Phylogenetic analyses revealed two major clades in L. souffia, an ‘Italian’ clade, and an ‘Alpine’ clade. Two hybrid zones exist, in the Mediterranean Alps and in the Soca basin. The position of the sister species of L. souffia, L. turskyi, to the ‘Alpine’ and the ‘Italian’ clade could not be resolved unambiguously. However, a linearized tree analysis indicated that L. turskyi represents a third lineage, that originated at the same time as the ‘Alpine’ and the ‘Italian’ clades of L. souffia. In the ‘Alpine’ clade two groups were resolved, a subclade with haplotypes from the Rhône and Var basins and a cluster with haplotypes from the Danube and Rhine systems. Our data suggest a long history of the vairone in Central Europe, predating Pleistocene glacial cycles. Two main refugia during glaciations must have existed, one in Italy and another one most probably in the Danube system. However, age estimates based on molecular clock calibrations suggest the survival of ‘Alpine’ haplotypes in several drainages during the last glaciation cycles. The Rhine system was only recently colonized.     

Phylogeography of noble crayfish (Astacus astacus) reveals multiple refugia

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Chloroplast sequences reveal a diversity gradient in the Mediterranean Ruppia cirrhosa species complex

Two subcosmopolitan species Ruppia maritima and Ruppia cirrhosa are recognized throughout Europe, whereas Ruppia drepanensis is endemic to SW Europe. We aimed at characterizing the geographic structure of the chloroplast DNA haplotype diversity of 56 Ruppia populations across the European part of the Mediterranean. On the basis of five cpDNA markers (total length of 2300 bp) 16 haplotypes were obtained for 1546 individuals. Three populations of R. maritima showed a single haplotype and differed in five insertions/deletions and 16 substitutions from a highly variable R. cirrhosa species complex, which included R. drepanensis. The haplotype diversity of this species complex was much higher in the western Mediterranean basin than in the eastern basin. Analysis of molecular variance (AMOVA) showed significant differentiation of R. cirrhosa between the two basins and also within the western Mediterranean thereby suggesting the latter as an important centre of Ruppia diversity. An isolation-by-distance (IBD) pattern was stronger between the West-East basin populations than within basins. A PCO analysis of the western basin populations indicated a diversity gradient with those of Sardinia as polymorph intermediates. The low diversity within the eastern basin suggests that the observed gradient could be hypothesized as a historical dispersal of only a limited number of haplotypes from west to east.     

Genetic variability of central–western European pine marten (Martes martes) populations

Recent studies highlighted the potential role of cryptic glacial refugia for temperate taxa in Europe beyond the Mediterranean peninsulas. To further investigate phylogeographic features of the European pine marten (Martes martes) in previously identified cryptic refugia located in central–western Europe, we analysed the hyper-variable diagnostic fragment of the mitochondrial control region in a total of 134 specimens, allowing for reliable comparisons with previous genetic studies of the species. We included samples from eight different European countries in central–western Europe (Belgium, France, Luxembourg and the Netherlands), in south–western Europe (Spain), in north–central Europe (Denmark) and in central Europe (Germany and Poland). The sequences collapsed in 17 haplotypes, which allowed us to determine the genetic composition of the pine marten populations throughout central–western Europe. Overall, our results showed that the population genetic variation, estimated by the standardised haplotype diversity, was high (0.400?≤?Hs?≤?0.762), and it was considerably higher in Germany (0.762) and the Netherlands (0.722) compared to the other countries. The nucleotide diversity was relatively low (0.002?≤?π?≤?0.016) even in Germany and the Netherlands (0.016 and 0.014, respectively), suggesting relatively small, long-term effective population sizes or severe bottlenecks. Out of the 17 haplotypes found in our study area, 13 were unique and limited to a single country: one in Denmark, one in Spain, four in Poland and seven in the Netherlands. The pairwise genetic distance ranged from 0.001 to 0.032 and did not show any evident correlation with the geographic distances between the populations. A genealogical relationship network was constructed, which provided evidence for a recent origin of many of the unique haplotypes. Approximately 82 % of the samples analysed in this study belonged to haplotypes grouped into a previously identified central–northern European phylogroup of the species. Our results support previous findings, indicating low contribution of southern refugial populations to the postglacial recolonization of central–western Europe and a predominant contribution of pine marten populations that survived the Last Glacial Maxima in cryptic northern refugia.     

Contrasting phylogeographic patterns in Sphagnum fimbriatum and Sphagnum squarrosum (Bryophyta, Sphagnopsida) in Europe

The chloroplast phylogeography of two peat mosses (Sphagnum fimbriatum and Sphagnum squarrosum) with similar distributions but different life history characteristics was investigated in Europe. Our main aim was to test whether similar distributions reflect similar phylogeographic and phylodemographic processes. Accessions covering the European distributions of the species were collected and approx. 2000 bp of the chloroplast genome of each species was sequenced. Maximum parsimony, statistical parsimony and phylodemographic analyses were used to address the question of whether these species with similar distributions show evidence of similar phylogeographic and phylodemographic processes. The chloroplast haplotypes of the currently spreading species S. fimbriatum showed strong geographic structure, whereas those of S. squarrosum, which has stable historical population sizes, showed only very weak geographic affinity and were widely distributed. We hypothesize that S. fimbriatum survived the last glaciations along the Atlantic coast of Europe, whereas S. squarrosum had numerous, scattered refugia in Europe. The dominance of one haplotype of S. fimbriatum across almost all of Europe suggests rapid colonization after the last glacial maximum. We hypothesize that high colonizing ability is an inherent characteristic of the species and its recent expansion in Europe is a response to climate change.     

Genetic diversity in Australian ancient asexual <Emphasis Type="Italic">Vestalenula</Emphasis> (Ostracoda,Darwinulidae): little variability down under

Darwinulid ostracods are putative ancient asexuals, and are thus assumed to be unable to purge deleterious mutations from their genomes. Some darwinulids species can be found both above (epigeic) and below ground (hypogeic). We hypothesize that surface populations carry more mutations than their below-ground counterparts, which are buffered from mutagens such as UV-B. Given the age of the investigated area, the Pilbara in Western Australia, we also expect geographic patterning of observed haplotypes. We have used DNA sequence data from the nuclear ITS and the mitochondrial COI region to investigate a (limited) data set on two Australian species, the endemic Vestalenula matildae and V. marmonieri from the Pilbara region. We do not find differences in genetic variability between specimens from subterranean habitats as compared to those from habitats above ground. There was also no congruence between hydrological basins and distribution patterns of the haplotypes identified. Although our data indicate that the two species may have split from each other ca. 70 myr ago, this has not resulted in any clear phylogeographic patterns among the analysed specimens across the regions of the Pilbara.     

Contrasting insights provided by single and multispecies data in a regional comparative phylogeographic study

Many single‐species freshwater phylogeographic studies have been carried out in south‐east Queensland; however comparative phylogeography requires multiple lines of evidence to infer deep, significant relationships between landscape and biota. The present study aimed to test conclusions resulting from single taxon studies in a multispecies comparative framework: (1) how influential are river basins in the genetic structure of freshwater species; (2) are there biogeographic frontiers between groups of basins; and (3) could deep intraspecific lineages be explained by a single event? New and existing data from 33 freshwater species (23 fishes and 10 crustaceans) were combined, and both standard single‐species analyses (haplotype networks, genetic distances, Φ_ST) and multispecies methods (hierarchical ABC) were carried out for 1814 sequences from eight basins. More than half of the species displayed a high phylogeographic structure and contained at least two distinct lineages. Almost all of the lineage divergences displayed an element of north/south geographic breaks, with the most influential boundary being between the Mary and Brisbane rivers. Of the 11 basin‐pair multispecies coalescent analyses, four implied a single divergence as being most likely. A regional analysis of deep lineages within 16 taxon‐pairs resulted in a strongly supported inference of a single divergence, probably dating to the Pleistocene. Basin boundaries are a key determinant of phylogeographic patterns for most of these freshwater species, although the specific biogeographic relationship between basins often varies depending on the species. There are a number of influential biogeographic frontiers, with the Brisbane‐Mary being the most important. The finding that a single event may be responsible for multiple deep lineages across the region implies that a highly influential climate change event may have been detected. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 554–569.     

Phylogeography of the bullhead Cottus gobio (Pisces: Teleostei: Cottidae) suggests a pre-pleistocene origin of the major central European populations

The bullhead Cottus gobio is a small, bottom-dwelling fish consisting of populations that have not been subject to transplantations or artificial stocking. It is therefore an ideal model species for studying the colonization history of central European freshwater systems, in particular with respect to the possible influences of the Pleistocene glaciation cycles. We sampled Cottus populations across most of its distribution range, with a special emphasis on southern Germany where the major European drainage systems are in closest contact. Mitochondrial D-loop sequencing of more than 400 specimens and phylogenetic network analysis allowed us to draw a detailed picture of the colonization of Europe by C. gobio. Moreover, the molecular distances between the haplotypes enabled us to infer an approximate time frame for the origin of the various populations. The founder population of C. gobio stems apparently from the Paratethys and invaded Europe in the Pliocene. From there, the first colonization into central Europe occurred via the ancient lower Danube, with a separate colonization of the eastern European territories. During the late Pliocene, one of the central European populations must have reached the North Sea in a second step after which it then started to colonize the Atlantic drainages via coastal lines. Accordingly, we found very distinct populations in the upper and lower Rhine, which can be explained by the fact that the lower Rhine was disconnected from the upper Rhine until approximately 1 million years ago (Ma). More closely related, but still distinct, populations were found in the Elbe, the Main and the upper Danube, all presumably of Pleistocene origin. Intriguingly, they have largely maintained their population identity, despite the strong disturbance caused by the glaciation cycles in these areas. On the other hand, a mixing of populations during postglacial recolonization could be detected in the lower Rhine and its tributaries. However, the general pattern that emerges from our analysis suggests that the glaciation cycles did not have a major impact on the general population structure of C. gobio in central Europe.     

Tracing recent invasions of the Ponto-Caspian mysid shrimp Hemimysis anomala across Europe and to North America with mitochondrial DNA

The mysid crustacean Hemimysis anomala ('bloody-red shrimp') is one of the most recent participants in the invasion of European inland waters by Ponto-Caspian species. Recently the species also became established in England and the Laurentian Great Lakes of North America. Using information from mitochondrial cytochrome oxidase I (COI) gene sequences, we traced the invasion pathways of H. anomala ; the inferences were enabled by the observed phylogeographical subdivision among the source area populations in the estuaries of the Ponto-Caspian basin. The data distinguish two routes to northern and western Europe used by distinct lineages. One route has been to and through the Baltic Sea and further to the Rhine delta, probably from a population intentionally introduced to a Lithuanian water reservoir from the lower Dnieper River (NW Black Sea area) in 1960. The other lineage is derived from the Danube delta and has spread across the continent up the Danube River and further through the Main–Danube canal down to the Rhine River delta. Only the Danube lineage was found in England and in North America. The two lineages appear to have met secondarily and are now found intermixed at several sites in NW Europe, including the Rhine and waters linked with the man-made Mittellandkanal that interconnects the Rhine and Baltic drainage systems.     

Vicariance, colonisation, and fast local speciation in Asia Minor and the Balkans as revealed from the phylogeny of spined loaches (Osteichthyes; Cobitidae)

We reconstruct the phylogeny of the morphologically diagnosable subgenera Bicanestrinia, Beysehiria, and Cobitis sensu stricto of the genus Cobitis from Asia Minor and the Balkans. We used the complete cytochrome b gene of 65 specimens in order to infer their evolutionary history in this zoogeographically interesting area. Our phylogeographic analysis did not evidence the previously suggested monophyly of the Bicanestrinia subgenus but revealed five monophyletic lineages in the area: the lineages Bicanestrinia I-IV including all species of Bicanestrinia plus the lineage Cobitis s. str. The monotypic subgenus Beysehiria from Lake Beysehir in Anatolia was closely related to the syntopic population of C. turcica and nested inside the lineage Bicanestrinia III. The strictly allopatric distribution of the four lineages of Bicanestrinia suggests that vicariance has played a major role in the diversification of Bicanestrinia. All analysed species of Cobitis s. str. from Asia Minor and Balkans were closely related to Cobitis s. str. from Central Europe, the Danube basin and the Caucasus, indicating at least two colonisation events into Asia Minor and the Balkans. A third, recent colonisation event led to the presence of C. strumicae, generally restricted to the Aegean Sea drainage, in the Danube basin. Besides the evidences of vicariance and colonisation events in the phylogenetic history of the genus Cobitis in Asia Minor and the Balkans, our analysis suggested also a rapid morphological evolution of C. bilseli in a lacustrine environment. Application of Cobitis mitochondrial cytochrome b clocks of 0.68% sequence divergence per million years (MY) suggest that the split between the five major lineages happened approximately 12.4-17.6 MYA, and according to the lack of basal resolution of this monophyletic group probably the split of all lineages happened within a narrow time window.     

So close and so different: comparative phylogeography of two small mammal species, the yellow-necked fieldmouse (Apodemus flavicollis) and the woodmouse (Apodemus sylvaticus) in the Western Palearctic region

In Europe, concordant geographical distribution among genetic lineages within different species is rare, which suggests distinct reactions to Quaternary ice ages. This study aims to determine whether such a discrepancy also affects a pair of sympatric species, which are morphologically and taxonomically closely related but which have slight differences in their ecological habits. The phylogeographic structures of two European rodents, the Yellow-necked fieldmouse (A. flavicollis) and the woodmouse (Apodemus sylvaticus) were, therefore, compared on the basis of mitochondrial DNA cytochrome b (mtDNA cyt b) sequences (965 base pairs) from 196 specimens collected from 59 European localities spread throughout the species distributions. The results indicate that the two species survived in different ways through the Quaternary glaciations. A. sylvaticus survived in the Iberian Peninsula from where it recolonized almost all Europe at the end of the last glaciation. Conversely, the refuge from which A. flavicollis recolonized Europe, including northern Spain, during the Holocene corresponds to the Italo-Balkan area, where A. sylvaticus suffered a serious genetic bottleneck. This study confirms that even closely related species may have highly different phylogeographic histories and shows the importance of ecological plasticity of the species for their survival through climate change. Finally, it suggests that phylogeographic distinctiveness may be a general feature of European species.     

Bathymetric and geographic population structure in the pan-Atlantic deep-sea bivalve Deminucula atacellana (Schenck, 1939)

The deep-sea soft-sediment environment hosts a diverse and highly endemic fauna of uncertain origin. We know little about how this fauna evolved because geographic patterns of genetic variation, the essential information for inferring patterns of population differentiation and speciation are poorly understood. Using formalin-fixed specimens from archival collections, we quantify patterns of genetic variation in the protobranch bivalve Deminucula atacellana, a species widespread throughout the Atlantic Ocean at bathyal and abyssal depths. Samples were taken from 18 localities in the North American, West European and Argentine basins. A hypervariable region of mitochondrial 16S rDNA was amplified by polymerase chain reaction (PCR) and sequenced from 130 individuals revealing 21 haplotypes. Except for several important exceptions, haplotypes are unique to each basin. Overall gene diversity is high (h = 0.73) with pronounced population structure (Phi(ST) = 0.877) and highly significant geographic associations (P < 0.0001). Sequences cluster into four major clades corresponding to differences in geography and depth. Genetic divergence was much greater among populations at different depths within the same basin, than among those at similar depths but separated by thousands of kilometres. Isolation by distance probably explains much of the interbasin variation. Depth-related divergence may reflect historical patterns of colonization or strong environmental selective gradients. Broadly distributed deep-sea organisms can possess highly genetically divergent populations, despite the lack of any morphological divergence.     

Phylogeography and postglacial dispersion of the chub (Leuciscus cephalus) in Europe

A phylogeographic analysis of mitochondrial DNA variation was performed in order to test the hypothesis of a postglacial recolonization of mid- and north-European rivers from a Danubian refuge. Over 345 chub specimens from European rivers covering most of the species' native range were investigated using 600 bp of the cytochrome b gene. Chub in European rivers belong to four highly divergent mitochondrial groups (lineages) differing by mean divergence estimates from 5.2% to 7.89%. These four lineages have a largely allopatric distribution, implying four geographical sets: two Mediterranean, and two north-European sets. This pattern provided strong evidence for: (i) the eradication of this species from most of Europe during maximum ice extent; (ii) its survival in four refugia (Adriatic side of the Balkans, eastern Greece (Aegean Rivers), southern tributaries of the Danube, and periphery of Black and Caspian Seas); (iii) a differential postglacial recolonization of mid- and northern Europe from the last two refugia only; (iv) the occurrence of this recolonization in two steps for the Danubian (western) lineage that entered western Europe (Rhine-Rhone-Loire drainages) during the Riss-Würm interglacial period and survived the last glaciation there before colonizing Garonne, UK and German drainages up to the Elbe during the Holocene; and (v) the occurrence of this recolonization in a single step for the Ponto-Caspian (eastern) lineage that entered the Baltic area as far as the Oder in the Holocene. Both lineages came into contact in the River Elbe without evident mixing.     

Multiple origins of European populations of the giant liver fluke Fascioloides magna (Trematoda: Fasciolidae), a liver parasite of ruminants

The giant liver fluke, Fascioloides magna, a liver parasite of free-living and domestic ruminants of Europe and North America, was analysed in order to determine the origin of European populations and to reveal the biogeography of this originally North American parasite on the European continent. The variable fragments of the mitochondrial cytochrome c oxidase subunit I (cox1; 384bp) and nicotinamide dehydrogenase subunit I (nad1; 405bp) were used. Phylogenetic trees and haplotype networks were constructed and the level of genetic structuring was evaluated using population genetic tools. In F. magna individuals originating from all European foci of infection (Italy, Czech Republic and Danube floodplain forests involving the territories of Slovakia, Hungary and Croatia) and from four of five major North American enzootic areas, 16 cox1 and 18 nad1 haplotypes were determined. The concatenated sequence set produced 22 distinct haplotypes. The European fluke populations were less diverse than those from North America in that they contained proportionately fewer haplotypes (eight), while a more substantial level of genetic diversity and a greater number of haplotypes (15) were recorded in North America. Only one haplotype was shared between the European (Italy) and North American (USA/Oregon and Canada/Alberta) flukes, supporting a western North American origin of the Italian F. magna population. Haplotypes found in Italy were distinct from those determined in the remaining European localities which indicates that introduction of F. magna to the European continent occurred more than once. In the Czech focus of infection, a south-eastern USA origin was revealed. Identical haplotypes, common to parasites from the Czech Republic and from an expanding focus in Danube floodplain forests, implies that the introduction of F. magna to the Danube region came from an already established Czech focus of infection.