Taxonomic differentiation of Cupressus sempervirens and C. atlantica based on morphometric evidence

We investigated the interspecific morphological relationships of two related Mediterranean Cupressus taxa and the possible geographic differentiation of Eastern Mediterranean C. sempervirens using morphometric analysis. A total of 446 individuals, representing eight C. atlantica (Morocco) and 10 C. sempervirens (Greece, Turkey and Lebanon) populations were examined. The 17 morphological characters of cone, seed and shoot with leaves were measured and analysed statistically. Significant morphological differences between C. atlantica and C. sempervirens were detected for the majority of analysed characters. For C. sempervirens, significant differences were also detected and these were related to its three regions of origin, the Greek Islands, Taurus Mts and Lebanon Mts. Multivariate analyses did not indicate a clear geographic pattern of differentiation in C. sempervirens populations. A relatively low level of phenotypic differentiation was detected between populations originating from the Greek Islands and Taurus Mts. We also observed a moderate multivariate differentiation between the Lebanese and remaining C. sempervirens populations. Phenotypic differentiation detected in the Asian part of the C. sempervirens range reflects patterns of differentiation similar to those described for other taxa occurring in the Taurus and Lebanon Mts.     

Central Asian origin of and strong genetic differentiation among populations of the rare and disjunct Carex atrofusca (Cyperaceae) in the Alps

Aim Carex atrofusca has an arctic–alpine distribution in the Northern Hemisphere, with only a few, disjunct localities known in the European Alps. These alpine populations are declining in number and size. In contrast, C. atrofusca has a wide circumpolar distribution range and is abundant in large parts of the Arctic. The degree of genetic differentiation of the alpine populations and their importance for the conservation of the intraspecific genetic variation of the species is unknown. Location Eurasia and Greenland, with emphasis on the European Alps. Methods We applied amplified fragment length polymorphism (AFLP) fingerprinting and sequences of chloroplast DNA to determine the position of the alpine populations in a circumpolar phylogeography of C. atrofusca and to unravel the patterns of genetic diversity and differentiation within the Alps. Results Two distinct major groups were detected in a neighbour‐joining analysis of AFLP data and in parsimony analysis of chloroplast DNA sequences: one consisting of the populations from Siberia and Greenland and one consisting of all European populations as sister to the populations from Central Asia. Within Europe, the populations from the Tatra Mountains and those from Scotland and Scandinavia formed two well‐supported groups, whereas the alpine populations did not constitute a group of their own. The genetic variation in the Alps was almost completely partitioned among the populations, and the populations were almost invariable. Main conclusions The alpine populations possibly originated due to immigration from Central Asia. The strong differentiation among them suggests that genetic drift has been strongly acting on the populations, either as a consequence of founder events during colonization or due to subsequent reduction of population sizes during warm stages of the Holocene.     

Inferences on population history of a seed chalcid wasp: invasion success despite a severe founder effect from an unexpected source population

Most invasive species established in Europe originate from either Asia or North America, but little is currently known about the potential of the Anatolian Peninsula (Asia Minor) and/or the Near East to constitute invasion sources. Mediterranean forests are generally fragile ecosystems that can be threatened by invasive organisms coming from different regions of the Mediterranean Basin, but for which historical data are difficult to gather and the phylogeographic patterns are still poorly understood for most terrestrial organisms. In this study, we characterized the genetic structure of Megastigmus schimitscheki, an invasive seed‐feeding insect species originating from the Near East, and elucidated its invasion route in South‐eastern France in the mid 1990s. To disentangle the evolutionary history of this introduction, we gathered samples from the main native regions (Taurus Mountains in Turkey, Lebanon and Cyprus) and from the invaded region that we genotyped using five microsatellite markers and for which we sequenced the mitochondrial Cytochrome Oxidase I gene. We applied a set of population genetic statistics and methods, including approximate Bayesian computation. We proposed a detailed phylogeographic pattern for the Near East populations, and we unambiguously showed that the French invasive populations originated from Cyprus, although the available historical data strongly suggested that Turkey could be the most plausible source area. Interestingly, we could show that the introduced populations were founded from an extremely restricted number of individuals that realized a host switch from Cedrus brevifolia to C. atlantica. Evolutionary hypotheses are discussed to account for this unlikely scenario.     

Global diversity and genetic contributions of chicken populations from African,Asian and European regions

Genetic diversity and population structure of 113 chicken populations from Africa, Asia and Europe were studied using 29 microsatellite markers. Among these, three populations of wild chickens and nine commercial purebreds were used as reference populations for comparison. Compared to commercial lines and chickens sampled from the European region, high mean numbers of alleles and a high degree of heterozygosity were found in Asian and African chickens as well as in Red Junglefowl. Population differentiation (F_ST) was higher among European breeds and commercial lines than among African, Asian and Red Junglefowl populations. Neighbour‐Net genetic clustering and structure analysis revealed two main groups of Asian and north‐west European breeds, whereas African populations overlap with other breeds from Eastern Europe and the Mediterranean region. Broilers and brown egg layers were situated between the Asian and north‐west European clusters. structure analysis confirmed a lower degree of population stratification in African and Asian chickens than in European breeds. High genetic differentiation and low genetic contributions to global diversity have been observed for single European breeds. Populations with low genetic variability have also shown a low genetic contribution to a core set of diversity in attaining maximum genetic variation present from the total populations. This may indicate that conservation measures in Europe should pay special attention to preserving as many single chicken breeds as possible to maintain maximum genetic diversity given that higher genetic variations come from differentiation between breeds.     

Microsatellite DNA markers indicate three genetic lineages in East Asian indigenous goat populations

The genetic differentiation and phylogenetic relationships of 18 indigenous goat populations from seven East Asian countries were analysed based on data obtained from 26 microsatellite DNA markers. The mean number of alleles (MNA) per population ranged from 2.5 to 7.6, with an average of 5.8. Genetic variability estimated from MNA and heterozygosity (H_E and H_O) were relatively low in coastal and island populations. A heterozygous deficiency within populations (F_IS = 0.054, P < 0.001) and total inbreeding (F_IT = 0.181, P < 0.01) were observed, and genetic differentiation in the populations (F_ST) was 13.4%. The results of Bayesian model‐based clustering and a neighbour‐joining tree based on Nei's genetic distance showed that Asian goat populations could be subdivided into at least the following three genetic clusters: East Asian, Southeast Asian and Mongolian. These results are in close accordance with conventional morphological and geographical classifications and migration history.     

Genetic biogeography of the rate “copper moss”,Scopelophila cataractae (Pottiaceae)

Scopelophila cataractae, one of the so-called copper mosses, has a broad geographic distribution that includes North, Central, and South America, Europe, and Asia, but is rare throughout its range. A genetic analysis of 32 populations from the United States, Europe, and Asia based on 15 putative allozyme loci indicates that levels of genetic diversity vary among geographic regions. Six European populations are fixed for the same alleles at all 15 loci, consistent with the hypothesis thatS. cataractae is a recent immigrant in that region. The species is more diverse in the U.S., where it appears to be native. Five populations collected on copper-enriched soils around shrines and temples in Tokyo are genetically monomorphic, but Asian populations from another Japanese site, India, and Nepal are exceptionally diverse in terms of numbers of alleles and multilocus haplotypes, total gene diversity (H_T), and in the degree of differentiation among populations (measured as Nei'sI andD). Long-distance dispersal has probably played an important role in the geographic history ofS. cataractae, but the species appears to be native in both the New and Old Worlds. Gene flow between plants disjunct on different continents is insufficient to explain the lack of geographically correlated morphological and genetic differentiation inS. cataractae.     

Genetic diversity and geographic differentiation of disjunct Atlantic and Amazonian populations of <Emphasis Type="Italic">Psychotria ipecacuanha</Emphasis> (Rubiaceae)

Ipecac (Psychotria ipecacuanha) is a perennial, medicinal herb that grows in the understory of semi-deciduous tropical forests in the Neotropics. Ipecacs present a widely disjunct distribution, with two of its three ranges occurring in Brazil. The Amazonian populations are at least 1600 km from the nearest Atlantic populations. This work used ISSR markers to compare the genetic diversity and structure of populations from the two Brazilian ranges. Lower genetic diversity in Amazon populations (P = 60.11%, Hs = 0.18) and higher genetic diversity in Atlantic populations (P = 73.94%, Hs = 0.20) were detected. Differentiation between ranges were high (θ ^B = 0.6838, G_ST-B = 0.6665). AMOVA revealed that 65.3% of the total molecular variance can be attributed to regional differences between the two ranges. Principal coordinate analyses and cluster analyses organized ipecacs at either individual or population level into two exclusive groups that correspond each to one of the two disjunct ranges, without exception. The results do not support a scenario that postulates human-mediated, long-distance dispersal events as a plausible origin for the distribution of the Brazilian ipecacs, but indicate geographic isolation as a long-standing barrier to genetic exchange and connectivity among populations from different ranges. Conservation implications are discussed.     

Population structure of the invasive forest pathogen Hymenoscyphus pseudoalbidus

Understanding the genetic diversity and structure of invasive pathogens in source and in introduced areas is crucial to the revelation of hidden biological features of an organism, to the reconstruction of the course of invasions and to the establishment of effective control measures. Hymenoscyphus pseudoalbidus (anamorph: Chalara fraxinea) is an invasive and highly destructive fungal pathogen found on common ash Fraxinus excelsior in Europe and is native to East Asia. To gain insights into its dispersal mechanisms and history of invasion, we used microsatellite markers and characterized the genetic structure and diversity of H. pseudoalbidus populations at three spatial levels: (i) between Europe and Japan, (ii) in Europe and (iii) at the epidemic's front in Switzerland. Phylogenetic and network analysis demonstrated that individuals from both regions are conspecific. However, populations from Japan harboured a higher genetic diversity and were genetically differentiated from European ones. No evident population structure was found among the 1208 European strains using Bayesian and multivariate clustering analysis. Only the distribution of genetic diversity in space, pairwise population differentiation (G_ST) and the spatial analysis of principal components revealed a faint geographical pattern around Europe. A significant allele deficiency in most European populations pointed to a recent genetic bottleneck, whereas no pattern of isolation by distance was found. Our data suggest that H. pseudoalbidus was introduced just once by at least two individuals. The potential source region of H. pseudoalbidus is vast, and further investigations are required for a more accurate localization of the source population.     

Population structure and migration of the Tobacco Blue Mold Pathogen,Peronospora tabacina,into North America and Europe

Tobacco blue mold, caused by Peronospora tabacina, is an oomycete plant pathogen that causes yearly epidemics in tobacco (Nicotiana tabacum) in the United States and Europe. The genetic structure of P. tabacina was examined to understand genetic diversity, population structure and patterns of migration. Two nuclear loci, Igs2 and Ypt1, and one mitochondrial locus, cox2, were amplified, cloned and sequenced from fifty‐four isolates of P. tabacina from the United States, Central America–Caribbean–Mexico (CCAM), Europe and the Middle East (EULE). Cloned sequences from the three genes showed high genetic variability across all populations. Nucleotide diversity and the population mean mutation parameter per site (Watterson's theta) were higher in EULE and CCAM and lower in U.S. populations. Neutrality tests were significant and the equilibrium model of neutral evolution was rejected, indicating an excess of recent mutations or rare alleles. Hudson's S_nn tests were performed to examine population subdivision and gene flow among populations. An isolation‐with‐migration analysis (IM) supported the hypothesis of long‐distance migration of P. tabacina from the Caribbean region, Florida and Texas into other states in the United States. Within the European populations, the model documented migration from North Central Europe into western Europe and Lebanon, and migration from western Europe into Lebanon. The migration patterns observed support historical observations about the first disease introductions and movement in Europe. The models developed are applicable to other aerial dispersed emerging pathogens and document that high‐evolutionary‐risk plant pathogens can move over long distances to cause disease due to their large effective population size, population expansion and dispersal.     

Assessing the phylogeographic history of the montane caddisfly Thremma gallicum using mitochondrial and restriction‐site‐associated DNA (RAD) markers

Repeated Quaternary glaciations have significantly shaped the present distribution and diversity of several European species in aquatic and terrestrial habitats. To study the phylogeography of freshwater invertebrates, patterns of intraspecific variation have been examined primarily using mitochondrial DNA markers that may yield results unrepresentative of the true species history. Here, population genetic parameters were inferred for a montane aquatic caddisfly, Thremma gallicum, by sequencing a 658‐bp fragment of the mitochondrial CO1 gene, and 12,514 nuclear RAD loci. T. gallicum has a highly disjunct distribution in southern and central Europe, with known populations in the Cantabrian Mountains, Pyrenees, Massif Central, and Black Forest. Both datasets represented rangewide sampling of T. gallicum. For the CO1 dataset, this included 352 specimens from 26 populations, and for the RAD dataset, 17 specimens from eight populations. We tested 20 competing phylogeographic scenarios using approximate Bayesian computation (ABC) and estimated genetic diversity patterns. Support for phylogeographic scenarios and diversity estimates differed between datasets with the RAD data favouring a southern origin of extant populations and indicating the Cantabrian Mountains and Massif Central populations to represent highly diverse populations as compared with the Pyrenees and Black Forest populations. The CO1 data supported a vicariance scenario (north–south) and yielded inconsistent diversity estimates. Permutation tests suggest that a few hundred polymorphic RAD SNPs are necessary for reliable parameter estimates. Our results highlight the potential of RAD and ABC‐based hypothesis testing to complement phylogeographic studies on non‐model species.     

Limited genetic diversity and high differentiation among the remnant adder (Vipera berus) populations in the Swiss and French Jura Mountains

Although the adder (Vipera berus) has a large distribution area, this species is particularly threatened in Western Europe due to high habitat fragmentation and human persecution. We developed 13 new microsatellite markers in order to evaluate population structure and genetic diversity in the Swiss and French Jura Mountains, where the species is limited to only a few scattered populations. We found that V. berus exhibits a considerable genetic differentiation among populations (global F_ST = 0.269), even if these are not geographically isolated. Moreover, the genetic diversity within populations in the Jura Mountains and in the less perturbed Swiss Alps is significantly lower than in other French populations, possibly due to post-glacial recolonisation processes. Finally, in order to minimize losses of genetic diversities within isolated populations, suggestions for the conservation of this species in fragmented habitats are proposed.     

Low population genetic differentiation in the Orchidaceae: implications for the diversification of the family

A leading hypothesis for the immense diversity of the Orchidaceae is that skewed mating success and small, disjunct populations lead to strong genetic drift and switches between adaptive peaks. This mechanism is only possible under conditions of low gene flow that lead to high genetic differentiation among populations. We tested whether orchids typically exhibit high levels of population genetic differentiation by conducting a meta‐analysis to compare mean levels of population genetic differentiation (F_ST) between orchids and other diverse families and between rare and common orchids. Compared with other families, the Orchidaceae is typically characterized by relatively low genetic differentiation among populations (mean F_ST = 0.146) at allozyme loci. Rare terrestrial orchids showed higher population genetic differentiation than common orchids, although this value was still lower than the mean for most plant families. All lines of evidence suggest that orchids are typically characterized by low levels of population genetic differentiation, even in species with naturally disjunct populations. As such, we found no strong evidence that genetic drift in isolated populations has played a major role in the diversification of the Orchidaceae. Further research into the diversification of the family needs to unravel the relative roles of biotic and environmental selective pressures in the speciation of orchids.     

Population structure and colonization of Bactrocera dorsalis (Diptera: Tephritidae) in China,inferred from mtDNA COI sequences

The oriental fruit fly, Bactrocera dorsalis, is a serious pest of fruits and vegetables in South‐east Asia, and, because of quarantine restrictions, impedes international trade and economic development in the region. Revealing genetic variation in oriental fruit fly populations will provide a better understanding of the colonization process and facilitate the quarantine and management of this species. The genetic structure in 15 populations of oriental fruit fly from southern China, Laos and Myanmar in South‐east Asia was examined with a 640‐bp sequence of the mitochondrial cytochrome oxidase subunit I (COI) gene. The highest levels of genetic diversity were found in Laos and Myanmar. Low to medium levels of genetic differentiation (F_ST ≤ 0.134) were observed among populations. Pooled populations from mainland China differed from those in Laos and Myanmar (F_ST = 0.024). Genetic structure across the region did not follow the isolation‐by‐distance model. The high genetic diversity observed in Laos and Myanmar supports the South‐east Asian origin of B. dorsalis. High genetic diversity and significant differentiation between some populations within mainland China indicate B. dorsalis populations have been established in the region for an extended period of time. High levels of genetic diversity observed among the five populations from Hainan Island and similarity between the Island and Chinese mainland populations indicate that B. dorsalis was introduced to Hainan from the mainland and has been on the island for many years. High genetic diversity in the recently established population in Shanghai (Pudong) suggests multiple introductions or a larger number of founders.     

Reticulate evolution patterns in western-Eurasian beeches

Reticulate evolution resulting from gene flow among diverged taxa was studied on the example of the Fagus sylvatica species complex in Europe and western Asia. F. sylvatica L. is one of the most widespread woody species of the Northern Hemisphere with two commonly recognized subspecies (namely, F. sylvatica subsp. sylvatica and F. sylvatica subsp. orientalis) and two putatively hybridogenous or intermediate taxa (F. moesiaca and F. taurica). Whereas the distribution of F. sylvatica subsp. sylvatica in Europe is almost continuous, the Asian range of F. sylvatica subsp. orientalis is fragmented into several larger regional populations. We studied genetic variation at 12 allozyme loci in 279 local subpopulations to assess whether previous contacts of regional populations left traces in their gene pools. Two approaches were used to infer potential reticulations: the reticulate network (Makarenkov and Legendre in J Comp Biol 11:195–212, 2004) and the neighbor-net network (Bryant and Moulton in Mol Biol Evol 21:255–265, 2004). A UPGMA dendrogram based on genetic distances between local populations revealed a high differentiation level within subsp. orientalis, whereby populations from Asia Minor, the Caucasus and the Alborz mts. were placed in different clusters. The reticulated network showed possible connections among adjacent populations, putatively resulting from previous contacts. The neighbor-net network also consisted of two major groups corresponding to F. sylvatica s. str. + F. moesiaca and F. orientalis including F. taurica. Regional populations of F. moesiaca are placed close to the basis of the European branch and are highly networked, indicating ambiguity in the phylogenetic signal. Similarly, three subgroups can be distinguished within the F. orientalis group and correspond well with broad regions of Asia Minor, the Caucasus and the Alborz. The Amanus regional population is intermediary between the subgroup of Asia Minor and the Caucasian subgroup. Crimean populations (i.e., putative hybrids) are placed near the basis of the subgraph. Two explanations of the observed reticulations are discussed: expansions and retreats of the range of beech associated with Pliocene and Pleistocene climatic fluctuations, resulting in contacts and exchanges of gene pools among regional populations, and sharing ancestral polymorphisms due to incomplete lineage sorting.     

European wildcat populations are subdivided into five main biogeographic groups: consequences of Pleistocene climate changes or recent anthropogenic fragmentation?

Extant populations of the European wildcat are fragmented across the continent, the likely consequence of recent extirpations due to habitat loss and over‐hunting. However, their underlying phylogeographic history has never been reconstructed. For testing the hypothesis that the European wildcat survived the Ice Age fragmented in Mediterranean refuges, we assayed the genetic variation at 31 microsatellites in 668 presumptive European wildcats sampled in 15 European countries. Moreover, to evaluate the extent of subspecies/population divergence and identify eventual wild × domestic cat hybrids, we genotyped 26 African wildcats from Sardinia and North Africa and 294 random‐bred domestic cats. Results of multivariate analyses and Bayesian clustering confirmed that the European wild and the domestic cats (plus the African wildcats) belong to two well‐differentiated clusters (average Ф_ST = 0.159, R_st  = 0.392, P > 0.001; Analysis of molecular variance [AMOVA]). We identified from c. 5% to 10% cryptic hybrids in southern and central European populations. In contrast, wild‐living cats in Hungary and Scotland showed deep signatures of genetic admixture and introgression with domestic cats. The European wildcats are subdivided into five main genetic clusters (average Ф_ST = 0.103, R_st  = 0.143, P > 0.001; AMOVA) corresponding to five biogeographic groups, respectively, distributed in the Iberian Peninsula, central Europe, central Germany, Italian Peninsula and the island of Sicily, and in north‐eastern Italy and northern Balkan regions (Dinaric Alps). Approximate Bayesian Computation simulations supported late Pleistocene–early Holocene population splittings (from c. 60 k to 10 k years ago), contemporary to the last Ice Age climatic changes. These results provide evidences for wildcat Mediterranean refuges in southwestern Europe, but the evolution history of eastern wildcat populations remains to be clarified. Historical genetic subdivisions suggest conservation strategies aimed at enhancing gene flow through the restoration of ecological corridors within each biogeographic units. Concomitantly, the risk of hybridization with free‐ranging domestic cats along corridor edges should be carefully monitored.     

From Asia to Europe across Siberia: phylogeography of the Siberian spined loach (Teleostei,Cobitidae)

We assessed the genetic variability of the Siberian spined loach Cobitis melanoleuca across its unusually broad distribution that encompasses areas greatly affected by Pleistocene glaciations. Due to extensive morphological variation among their populations, the taxonomic status of C. melanoleuca is complicated. It is unclear whether C. melanoleuca represents a single taxonomic unit or contains several species or subspecies. Our analyses showed low genetic variability in all populations without any phylogenetic structure. The absence of molecular distinctiveness indicates the conspecificity of all C. melanoleuca populations. Only a few common haplotypes shared by East Asian, Siberian and European populations were found at high frequency in the nuclear genes analysed. At the mitochondrial level, Siberian populations shared haplotypes with populations located at both extremes of the species’ range suggesting central populations as a source of current mitochondrial variability. Unimodal mismatch distributions and significant values from neutrality tests support a recent expansion of C. melanoleuca. Our time estimates suggest a postglacial colonisation of European waters around 1.0 MYA, indicating that C. melanoleuca may represent the last cobitid immigrant in Europe that used the northern route across Siberia to expand its range.     

Identification of conservation units in the European Mergus merganser based on nuclear and mitochondrial DNA markers

The conservation status of small breeding areas of the Goosander (Mergus merganser merganser) in Central Europe is unclear. Geographic isolation of these areas suggests restricted gene flow to and from large North-European populations. On the other hand, migrating Goosanders from northern Europe join the Central European breeding population for wintering. To evaluate the conservation status of the small breeding areas we assessed the genetic structure of M. merganser populations in Europe by examining two nuclear marker systems (microsatellites and Single Nucleotide Polymorphisms, SNP) and mitochondrial (mtDNA) control region sequence variation for Goosanders in 11 sampling areas representing three of five distinct breeding areas and two subspecies (M. m. merganser and M. m. americanus). Overall population differentiation estimates including both subspecies were high, both based on mtDNA () and nuclear markers (θ _ST = 0.219; 95% CI 0.088–0.398, SNP and microsatellites combined). Within Europe, mtDNA revealed a strong overall () and significant pairwise population differentiation between almost all comparisons. In contrast, both nuclear marker systems combined revealed only a small overall genetic differentiation (θ _ST = 0.022; 95% CI 0.003–0.041). The strong genetic differentiation based on female-inherited mtDNA but not on biparentally inherited nuclear markers can be explained by sex-biased dispersal and strong female philopatry. Therefore, small breeding areas in Europe are endangered despite large male-mediated gene-flow, because when these populations decline, only males—but due to strong philopatry not females—can be efficiently supplemented by migration from the large North European populations. We therefore propose to manage the small breeding areas independently and to strengthen conservation efforts for this species in Central Europe.     

Genetic diversity and population differentiation of Capparis spinosa (Capparaceae) in Northwestern China

To explore the influence of vicariance on differentiation patterns of taxa in arid regions, we systematically assessed the genetic diversity and variability of Capparis spinosa, a typical xerophyte that is widely distributed in the Tianshan Mountains and adjacent areas. In total, 300 individuals from 25 populations were sampled, and 14 haplotypes were identified using two cpDNA sequences (rpS12-rpL20 and ndhF). A high level of total genetic diversity (H_T = 0.859) was detected, and this was attributed to the extensive distribution range, which included numerous large populations. The SAMOVA results suggested that the 25 populations were clustered into 4 major geographical groups; a similar divergence trend was found by constructing a BEAST phylogenetic tree and a network diagram. The AMOVA results revealed that significant genetic differentiation occurred among groups. Our results indicated a considerable correlation between genetic divergence and geographical distribution. Isolation due to complex mountain and desert geography might limit gene exchange between disjunct populations, resulting in high differentiation between geographical groups.     

Genetic variability,local selection and demographic history: genomic evidence of evolving towards allopatric speciation in Asian seabass

Genomewide analysis of genetic divergence is critically important in understanding the genetic processes of allopatric speciation. We sequenced RAD tags of 131 Asian seabass individuals of six populations from South‐East Asia and Australia/Papua New Guinea. Using 32 433 SNPs, we examined the genetic diversity and patterns of population differentiation across all the populations. We found significant evidence of genetic heterogeneity between South‐East Asian and Australian/Papua New Guinean populations. The Australian/Papua New Guinean populations showed a rather lower level of genetic diversity. F_ST and principal components analysis revealed striking divergence between South‐East Asian and Australian/Papua New Guinean populations. Interestingly, no evidence of contemporary gene flow was observed. The demographic history was further tested based on the folded joint site frequency spectrum. The scenario of ancient migration with historical population size changes was suggested to be the best fit model to explain the genetic divergence of Asian seabass between South‐East Asia and Australia/Papua New Guinea. This scenario also revealed that Australian/Papua New Guinean populations were founded by ancestors from South‐East Asia during mid‐Pleistocene and were completely isolated from the ancestral population after the last glacial retreat. We also detected footprints of local selection, which might be related to differential ecological adaptation. The ancient gene flow was examined and deemed likely insufficient to counteract the genetic differentiation caused by genetic drift. The observed genomic pattern of divergence conflicted with the ‘genomic islands’ scenario. Altogether, Asian seabass have likely been evolving towards allopatric speciation since the split from the ancestral population during mid‐Pleistocene.     

Surprising diversity in the Pannonian populations of Marsh Fritillary (Euphydryas aurinia,Lepidoptera: Nymphalidae): Morphometric and molecular aspects

Since genetic variation is the basis of evolutionary potential of a species, its structure needs to be understood. Thus, the aim of this study was to analyze and contrast the structure of genetic and phenotypic variation in the Euphydryas aurinia populations of southeastern central Europe. Genetic variation was studied by two types of molecular genetic markers: mtDNA COI sequences and allozymes. As the great hiatus in the European distribution of E. aurinia is located in the central part of the Carpathian Basin, we expected that the populations East and West to this gap would be highly differentiated. Populations of Central Transdanubia actually represent the easternmost margin of the West European distribution of E. aurinia. In view of the peripheral position of these populations, we supposed to find some genetic sign of local adaptation, as a consequence of diversifying selection and an increased level of fluctuating asymmetry as a result of environmental stress. The analyses of the molecular genetic markers revealed a basic East–West differentiation among the populations of southeastern central Europe which was further structured in the western part of the study area. The results suggested that the genetic differentiation between the two western regions is probably the consequence of diversifying selection. The pattern of phenotypic differentiation among the western populations, however, was different. A geographic cline was revealed (decreasing wing size) toward the eastern margin of the distribution in parallel with increasing fluctuating asymmetry. The conservation inferences of the results are considered.