Genetic divergence and phylogeographic relationships among european perch (Perca fluviatilis) populations reflect glacial refugia and postglacial colonization

We used the widely distributed freshwater fish, perch (Perca fluviatilis), to investigate the postglacial colonization routes of freshwater fishes in Europe. Genetic variability within and among drainages was assessed using mitochondrial DNA (mtDNA) D-loop sequencing and RAPD markers from 55 populations all over Europe as well as one Siberian population. High level of structuring for both markers was observed among drainages and regions, while little differentiation was seen within drainages and regions. Phylogeographic relationships among European perch were determined from the distribution of 35 mtDNA haplotypes detected in the samples. In addition to a distinct southern European group, which includes a Greek and a southern Danubian population, three major groups of perch are observed: the western European drainages, the eastern European drainages including the Siberian population, and Norwegian populations from northern Norway, and western side of Oslofjord. Our data suggest that present perch populations in western and northern Europe were colonized from three main refugia, located in southeastern, northeastern and western Europe. In support of this, nested cladistic analysis of mtDNA clade and nested clade distances suggested historical range expansion as the main factor determining geographical distribution of haplotypes. The Baltic Sea has been colonized from all three refugia, and northeastern Europe harbours descendants from both eastern European refugia. In the upper part of the Danube lineages from the western European and the southern European refugia meet. The southern European refugium probably did not contribute to the recolonization of other western and northern European drainages after the last glaciation. However, phylogenetic analyses suggest that the southern European mtDNA lineage is the most ancient, and therefore likely to be the founder of all present perch lineages. The colonization routes used by perch probably also apply to other freshwater species with similar distribution patterns.     

Genetic structure and colonization processes in European populations of the common vole, Microtus arvalis

The level of genetic differentiation within and between evolutionary lineages of the common vole (Microtus arvalis) in Europe was examined by analyzing mitochondrial sequences from the control region (mtDNA) and 12 nuclear microsatellite loci (nucDNA) for 338 voles from 18 populations. The distribution of evolutionary lineages and the affinity of populations to lineages were determined with additional sequence data from the mitochondrial cytochrome b gene. Our analyses demonstrated very high levels of differentiation between populations (overall FST: mtDNA 70%; nucDNA 17%). The affinity of populations to evolutionary lineages was strongly reflected in mtDNA but not in nucDNA variation. Patterns of genetic structure for both markers visualized in synthetic genetic maps suggest a postglacial range expansion of the species into the Alps, as well as a potentially more ancient colonization from the northeast to the southwest of Europe. This expansion is supported by estimates for the divergence times between evolutionary lineages and within the western European lineage, which predate the last glacial maximum (LGM). Furthermore, all measures of genetic diversity within populations increased significantly with longitude and showed a trend toward increase with latitude. We conclude that the detected patterns are difficult to explain only by range expansions from separate LGM refugia close to the Mediterranean. This suggests that some M. arvalis populations persisted during the LGM in suitable habitat further north and that the gradients in genetic diversity may represent traces of a more ancient colonization of Europe by the species.     

Repeated jumps from Northwest Africa to the European continent: The case of peripheral populations of an annual plant

Peripheral populations (i.e., those occurring on the edge of a species’ distribution range) can have different origins and genetic characteristics, and they may be critical for the conservation of genetic diversity. We investigated European peripheral populations of Scrophularia arguta, a widespread, annual plant distributed from Arabia to Northwest Africa and Macaronesia. Only two small disjunct population groups of this species occur in Europe, specifically in West‐Central and Southeast Iberia. To disclose the origin of these populations and determine their importance for the conservation of S. arguta genetic diversity, we analyzed DNA sequences from two nuclear and two plastid regions and amplified fragment length polymorphism markers in populations sampled mainly across the western distribution range of the species, and modeled the species distribution under present and late Quaternary conditions. The analyses revealed the presence of three distinct lineages of S. arguta in Europe, as a result of multiple colonization waves at different times in the Quaternary. Two of these lineages, occurring in Southeast Iberia, are the result of more or less recent dispersal from Northwest Africa. In contrast, West‐Central Iberian populations are strongly differentiated from the remaining range of S. arguta and can be considered as peripheral relict populations. Our study is the first to demonstrate the occurrence of at least three colonizations of the European continent from Africa by a native plant species. The diverse histories and genetic makeup of the resulting populations confirm the importance of peripheral populations, and particularly of ancient relict populations, for the conservation of global genetic diversity in widespread species.     

Multiple Pleistocene refugia and post‐glacial colonization in the European chub (Squalius cephalus) revealed by combined use of nuclear and mitochondrial markers

Aim To analyse patterns of nuclear and mitochondrial genetic variation in the European chub, Squalius cephalus (Linnaeus, 1758), in order to understand the evolutionary history of this species and to test biogeographical hypotheses for the existence of co‐distributed European freshwater fish species. Location Rivers in Europe (Finland, Poland, Czech Republic, France, Bulgaria, Spain, Italy). Methods We genotyped 12 polymorphic microsatellite markers derived from 310 individuals collected from across the distribution of S. cephalus in Europe (including a total of 15 populations) and sequenced mitochondrial DNA (mtDNA) from a subset of 75 individuals. Sequences of mtDNA cytochrome b were analysed using both phylogenetic (median‐joining networks) and population genetic methods (tests for demographic history, mismatch distributions, Bayesian coalescent analysis). Geographical structure in microsatellite loci was examined using a distance method (F_ST), factorial correspondence analysis (FCA) and a Bayesian clustering method (structure ). Results The mtDNA network showed a clear split into four different haplogroup lineages: Western (separated into Atlantic and Danubian sublineages), Eastern, Aegean (occurring in two distinct sublineages in the Balkans and in Spain) and Adriatic. Our results indicate recent population expansion in the Eastern and Western Atlantic lineages and the admixture of two previously separate sublineages (Atlantic and Danubian) in the Western lineage. Bayesian structure analysis as well as FCA results roughly corresponded to the mtDNA‐based structure, separating the sampled individuals into almost non‐overlapping groups. Main conclusions Our results support hypotheses suggesting origins of extant lineages of freshwater fishes in multiple refugia and the subsequent post‐glacial colonization of Europe via different routes. We confirmed the previously proposed two‐step expansion scenario from the Danube refuge, the existence of a secondary (Atlantic) refuge during the last glaciation (probably in the Rhone River) and population expansion of this lineage. Conspicuous divergences among Mediterranean populations reflect their different origin, as well as their low contribution to the recent genetic pool of chub in central Europe.     

Differentiation of mitochondrial DNA and Y chromosomes in Russian populations

The genetic composition of the Russian population was investigated by analyzing both mitochondrial DNA (mtDNA) and Y-chromosome loci polymorphisms that allow for the different components of a population gene pool to be studied, depending on the mode of DNA marker inheritance. mtDNA sequence variation was examined by using hypervariable segment I (HVSI) sequencing and restriction analysis of the haplogroup-specific sites in 325 individuals representing 5 Russian populations from the European part of Russia. The Y-chromosome variation was investigated in 338 individuals from 8 Russian populations (including 5 populations analyzed for mtDNA variation) using 12 binary markers. For both uniparental systems most of the observed haplogroups fell into major West Eurasian haplogroups (97.9% and 99.7% for mtDNA and Y-chromosome haplogroups, respectively). Multidimensional scaling analysis based on pairwise F(ST) values between mtDNA HVSI sequences in Russians compared to other European populations revealed a considerable heterogeneity of Russian populations; populations from the southern and western parts of Russia are separated from eastern and northern populations. Meanwhile, the multidimensional scaling analysis based on Y-chromosome haplogroup F(ST) values demonstrates that the Russian gene pool is close to central-eastern European populations, with a much higher similarity to the Baltic and Finno-Ugric male pools from northern European Russia. This discrepancy in the depth of penetration of mtDNA and Y-chromosome lineages characteristic for the most southwestern Russian populations into the east and north of eastern Europe appears to indicate that Russian colonization of the northeastern territories might have been accomplished mainly by males rather than by females.     

Unexpected population genetic structure of European roe deer in Poland: an invasion of the mtDNA genome from Siberian roe deer

Introgressive hybridization is a widespread evolutionary phenomenon which may lead to increased allelic variation at selective neutral loci and to transfer of fitness‐related traits to introgressed lineages. We inferred the population genetic structure of the European roe deer (Capreolus capreolus) in Poland from mitochondrial (CR and cyt b) and sex‐linked markers (ZFX, SRY, DBY4 and DBY8). Analyses of CR mtDNA sequences from 452 individuals indicated widespread introgression of Siberian roe deer (C. pygargus) mtDNA in the European roe deer genome, 2000 km from the current distribution range of C. pygargus. Introgressed individuals constituted 16.6% of the deer studied. Nearly 75% of them possessed haplotypes belonging to the group which arose 23 kyr ago and have not been detected within the natural range of Siberian roe deer, indicating that majority of present introgression has ancient origin. Unlike the mtDNA results, sex‐specific markers did not show signs of introgression. Species distribution modelling analyses suggested that C. pygargus could have extended its range as far west as Central Europe after last glacial maximum. The main hybridization event was probably associated with range expansion of the most abundant European roe deer lineage from western refugia and took place in Central Europe after the Younger Dryas (10.8–10.0 ka BP). Initially, introgressed mtDNA variants could have spread out on the wave of expansion through the mechanism of gene surfing, reaching high frequencies in European roe deer populations and leading to observed asymmetrical gene flow. Human‐mediated introductions of C. pygargus had minimal effect on the extent of mtDNA introgression.     

Discriminating the impact of recent human mediated stock transfer from historical gene flow on genetic structure of European grayling Thymallus thymallus L.

Microsatellite markers were first used to partition individuals of European grayling Thymallus thymallus , from the Danube, Rhine and Main, and Elbe drainage systems into subpopulations and to estimate individual immigrant ancestries over the last few generations. Subsequently, the studied populations were 'purged' from recent immigrants and the proportions of evolutionary lineages within the 'purged' populations were re-estimated by applying mtDNA markers. The results confirmed a high level of admixture of the divergent mtDNA lineages ( i.e. natural secondary contact) in populations sampled at the contact zones of the drainages. In addition, a substantial amount of introgression was observed for several populations that were known to be affected by stocking of European grayling from different origins.     

Evolutionary history of the greater white-toothed shrew (Crocidura russula) inferred from analysis of mtDNA, Y, and X chromosome markers

We investigate the evolutionary history of the greater white-toothed shrew across its distribution in northern Africa and mainland Europe using sex-specific (mtDNA and Y chromosome) and biparental (X chromosome) markers. All three loci confirm a large divergence between eastern (Tunisia and Sardinia) and western (Morocco and mainland Europe) lineages, and application of a molecular clock to mtDNA divergence estimates indicates a more ancient separation (2.25 M yr ago) than described by some previous studies, supporting claims for taxonomic revision. Moroccan ancestry for the mainland European population is inconclusive from phylogenetic trees, but is supported by greater nucleotide diversity and a more ancient population expansion in Morocco than in Europe. Signatures of rapid population expansion in mtDNA, combined with low X and Y chromosome diversity, suggest a single colonization of mainland Europe by a small number of Moroccan shrews >38 K yr ago. This study illustrates that multilocus genetic analyses can facilitate the interpretation of species' evolutionary history but that phylogeographic inference using X and Y chromosomes is restricted by low levels of observed polymorphism.     

Parapatric diversification after post-glacial range expansion in the gall fly Urophora cardui (Tephritidae)

Aim Primary and secondary genetic clines in post-glacial colonized regions have different implications for biogeographic distributions and the origin of species. Primary clines arise in situ after colonization as adaptive responses to environmental gradients, while secondary clines are caused by contact between vicariant lineages. Here we analyse primary versus secondary origin of a genetic cline in the tephritid fly Urophora cardui in Jutland, Denmark, in a post-glacial landscape. Location Western Palaearctic. Methods Phylogeographic and demographic analyses of U. cardui based on mitochondrial DNA (mtDNA) genealogies, hierarchical genetic variance tests based on allozymes and distribution analysis of a rare allele from the Jutland cline. Results There was no phylogeographic divergence between the Jutland population of U. cardui north of the cline and neighbouring western European regional populations, which all shared the common western European mtDNA haplotype H1. At nuclear loci, by contrast, the North Jutland population was diverged above the mean level of divergence among regional populations and had no loss of genetic variation. A rare allozyme allele that was frequent in the cline area (up to 45%) and was missing north of the cline also occurred at low frequency (0–14%) elsewhere in the sampling range. Shallow phylogeographic divergence was observed between Russian and western European populations and between English and continental populations. Main conclusions The genetic variation patterns support primary cline evolution and parapatric divergence in Jutland following a demographic expansion of a western European ancestral source population of U. cardui, and suggest cryptic refugia and/or selection in other European population assemblages. The patterns of intra-specific regional divergence are discussed with respect to the interpretation of cryptic refugia in Europe after the most recent ice age.     

Georgian and kurd mtDNA sequence analysis shows a lack of correlation between languages and female genetic lineages

Mitochondrial DNA sequences from Georgians and Kurds were analyzed in order to test the possible correlation between female lineages and languages in these two neighboring West Eurasian groups. Mitochondrial sequence pools in both populations are very similar despite their different linguistic and prehistoric backgrounds. Both populations present mtDNA lineages that clearly belong to the European gene pool, as shown by 1) similar nucleotide and sequence diversities; 2) a large number of sequences shared with the rest of European samples; 3) nonsignificant genetic distances; and 4) classification of the present lineages into the major European mtDNA haplogroups already described. The outlier position of the populations from the Caucasus according to classical genetic markers is not recognized in the present Georgian mtDNA sequence pool. This result suggests that the differentiation of mtDNA sequences in West Eurasia and the outlier features of Caucasian populations should be attributed to different processes. Moreover, the putative linguistic relationship between Caucasian groups and the Basques, another outlier population within Europe for classical genetic markers, is not detected by the analysis of mtDNA sequences.     

Contrasting patterns of mitochondrial and microsatellite genetic structure among Western European populations of tawny owls (Strix aluco)

A recent study of mitochondrial phylogeography of tawny owls (Strix aluco) in western Europe suggested that this species survived the Pleistocene glaciations in three allopatric refugia located in Iberia, Italy, and the Balkans, and the latter was likely the predominant source of postglacial colonization of northern Europe. New data from seven microsatellite loci from 184 individual owls distributed among 14 populations were used to assess the genetic congruence between nuclear and mitochondrial DNA (mtDNA) markers. Microsatellites corroborated the major phylogeographical conclusions reached on the basis of the mtDNA sequences, but also showed important differences leading to novel inferences. Microsatellites corroborated the three major refugia and supported the Balkan origin of northern populations. When corrected for differences in effective population size, microsatellites and mtDNA yielded generally congruent overall estimates of population structure (N*ST=0.12 vs. RST=0.16); however, there was substantial heterogeneity in the RST among the seven nuclear loci that was not correlated with heterozygosity. Populations representing the Balkans postglacial expansion interact with populations from the other two refugia forming two clines near the Alps and the Pyrenees. In both cases, the apparent position of the contact zones differed substantially between markers due to the genetic composition of populations sampled in northern Italy and Madrid. Microsatellite data did not corroborate the lower genetic diversity of northern, recently populated regions as was found with mtDNA; this discrepancy was taken as evidence for a recent bottleneck recovery. Finally, this study suggests that congruence among genetic markers should be more likely in cases of range expansion into new areas than when populations interact across contact zones.     

The Longue Durée of genetic ancestry: multiple genetic marker systems and Celtic origins on the Atlantic facade of Europe

Celtic languages are now spoken only on the Atlantic facade of Europe, mainly in Britain and Ireland, but were spoken more widely in western and central Europe until the collapse of the Roman Empire in the first millennium a.d. It has been common to couple archaeological evidence for the expansion of Iron Age elites in central Europe with the dispersal of these languages and of Celtic ethnicity and to posit a central European "homeland" for the Celtic peoples. More recently, however, archaeologists have questioned this "migrationist" view of Celtic ethnogenesis. The proposition of a central European ancestry should be testable by examining the distribution of genetic markers; however, although Y-chromosome patterns in Atlantic Europe show little evidence of central European influence, there has hitherto been insufficient data to confirm this by use of mitochondrial DNA (mtDNA). Here, we present both new mtDNA data from Ireland and a novel analysis of a greatly enlarged European mtDNA database. We show that mtDNA lineages, when analyzed in sufficiently large numbers, display patterns significantly similar to a large fraction of both Y-chromosome and autosomal variation. These multiple genetic marker systems indicate a shared ancestry throughout the Atlantic zone, from northern Iberia to western Scandinavia, that dates back to the end of the last Ice Age.     

Mitochondrial DNA variation and the evolutionary history of cryptic Gammarus fossarum types

The evolutionary history of the cryptic Gammarus fossarum species complex (Crustacea, Amphipoda) in Central Europe was approached by investigating the genetic variation in populations of a natural contact zone. Nucleotide sequence variation of a 395-bp segment of the mitochondrial 16S rRNA gene was compared to that of six nuclear allozyme loci. Three major mtDNA lineages were found, the eastern clade being consistent with the former allozyme type A. The two western clades (types B and C) were not distinguished previously. Strong sequence divergence and correlation with nuclear genetic isolation in syntopic populations, however, justifies the specific status of the three G. fossarum types. The common speciation event is believed to be very old (Miocene). The within-type mtDNA variation is probably molded by the ice ages, with type B populations being most affected. Moreover, the patch-like distribution of mtDNA type B lineages in an area near the contact zone corroborates the hypothesis of a recent colonization.     

Maternal genomic variability of the wild boar (Sus scrofa) reveals the uniqueness of East‐Caucasian and Central Italian populations

The phylogeography of the European wild boar was mainly determined by postglacial recolonization patterns from Mediterranean refugia after the last ice age. Here we present the first analysis of SNP polymorphism within the complete mtDNA genome of West Russian (n = 8), European (n = 64), and North African (n = 5) wild boar. Our analyses provided evidence of unique lineages in the East‐Caucasian (Dagestan) region and in Central Italy. A phylogenetic analysis revealed that these lineages are basal to the other European mtDNA sequences. We also show close connection between the Western Siberian and Eastern European populations. Also, the North African samples were clustered with the Iberian population. Phylogenetic trees and migration modeling revealed a high proximity of Dagestan sequences to those of Central Italy and suggested possible gene flow between Western Asia and Southern Europe which was not directly related to Northern and Central European lineages. Our results support the presence of old maternal lineages in two Southern glacial refugia (i.e., Caucasus and the Italian peninsula), as a legacy of an ancient wave of colonization of Southern Europe from an Eastern origin.     

Y‐chromosome evidence supports widespread signatures of three‐species Canis hybridization in eastern North America

There has been considerable discussion on the origin of the red wolf and eastern wolf and their evolution independent of the gray wolf. We analyzed mitochondrial DNA (mtDNA) and a Y‐chromosome intron sequence in combination with Y‐chromosome microsatellites from wolves and coyotes within the range of extensive wolf–coyote hybridization, that is, eastern North America. The detection of divergent Y‐chromosome haplotypes in the historic range of the eastern wolf is concordant with earlier mtDNA findings, and the absence of these haplotypes in western coyotes supports the existence of the North American evolved eastern wolf (Canis lycaon). Having haplotypes observed exclusively in eastern North America as a result of insufficient sampling in the historic range of the coyote or that these lineages subsequently went extinct in western geographies is unlikely given that eastern‐specific mtDNA and Y‐chromosome haplotypes represent lineages divergent from those observed in extant western coyotes. By combining Y‐chromosome and mtDNA distributional patterns, we identified hybrid genomes of eastern wolf, coyote, gray wolf, and potentially dog origin in Canis populations of central and eastern North America. The natural contemporary eastern Canis populations represent an important example of widespread introgression resulting in hybrid genomes across the original C. lycaon range that appears to be facilitated by the eastern wolf acting as a conduit for hybridization. Applying conventional taxonomic nomenclature and species‐based conservation initiatives, particularly in human‐modified landscapes, may be counterproductive to the effective management of these hybrids and fails to consider their evolutionary potential.     

Mitochondrial DNA phylogeography of the three-spined stickleback (Gasterosteus aculeatus) in Europe-evidence for multiple glacial refugia

An analysis of mitochondrial DNA sequence variation in 172 three-spined sticklebacks (Gasterosteus aculeatus) sampled across the European distribution range revealed three major evolutionary lineages occupying relatively large and separate geographic areas. The trans-Atlantic lineage comprised of populations spanning from the East Coast of USA to the continental Europe and was basal group to the other European lineages in the phylogeny. The European lineage included populations located in the Western and Eastern Europe, British Isles, Scandinavia as well as some parts of the Mediterranean region. The third lineage was specific to the Black Sea drainages. The within lineage structure was characterized by significant excess of low frequency haplotypes and star-like mtDNA genealogies, which suggest a recent population expansions to the formerly glaciated marine and freshwater environments. A coalescent-based method dated the splits between the major lineages to have occurred during the Saalian and Weichselian glaciations in the late Pleistocene, depending on the molecular clock calibration. The coalescent simulations further indicate high degree of genetic diversity within the lineages and a substantial increase in the genetic diversity in the European lineage relative to the ancestral level. In addition to the three major lineages, the freshwater populations in R. Neretva and L. Skadar in the Adriatic Sea coast region harboured unique and highly divergent haplotypes suggesting long independent histories of these populations. Evidence from mtDNA analyses suggests that these populations deserve a status of an evolutionary significant unit.     

Postglacial colonization of Europe by the barbastelle bat: agreement between molecular data and past predictive modelling

The barbastelle (Barbastella barbastellus) is a rare forest bat with a wide distribution in Europe. Here, we combine results from the analysis of two mtDNA fragments with species distribution modelling to determine glacial refugia and postglacial colonization routes. We also investigated whether niche conservatism occurs in this species. Glacial refugia were identified in the three southern European peninsulas: Iberia, Italy and the Balkans. These latter two refugia played a major role in the postglacial colonization process, with their populations expanding to England and central Europe, respectively. Palaeo‐distribution models predicted that suitable climatic conditions existed in the inferred refugia during the last glacial maximum (LGM). Nevertheless, the overlap between the current and the LGM distributions was almost inexistent in Italy and in the Balkans, meaning that B. barbastellus populations were forced to shift range between glacial and interglacial periods, a process that probably caused some local extinctions. In contrast, Iberian populations showed a ‘refugia within refugium’ pattern, with two unconnected areas containing stable populations (populations that subsisted during both glacial and interglacial phases). Moreover, the match between LGM models and the refugial areas determined by molecular analysis supported the hypothesis of niche conservatism in B. barbastellus. We argue that geographic patterns of genetic structuring, altogether with the modelling results, indicate the existence of four management units for conservation: Morocco, Iberia, Italy and UK, and Balkans and central Europe. In addition, all countries sampled possessed unique gene pools, thus stressing the need for the conservation of local populations.     

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.     

Macro-scale assessment of demographic and environmental variation within genetically derived evolutionary lineages of eastern hemlock (<Emphasis Type="Italic">Tsuga canadensis</Emphasis>), an imperiled conifer of the eastern United States

Eastern hemlock (Tsuga canadensis) occupies a large swath of eastern North America and has historically undergone range expansion and contraction resulting in several genetically separate lineages. This conifer is currently experiencing mortality across most of its range following infestation of a non-native insect. With the goal of better understanding the current and future conservation potential of the species, we evaluate ecological differences among populations within these genetically defined clusters, which were previously inferred using nuclear microsatellite molecular markers from 58 eastern hemlock populations. We sub-divide these clusters into four genetic zones to differentiate putative north-central, north-east and southeast (SE) and southwest evolutionary lineages in eastern hemlock. We use demographic data (relative abundance, mortality, and seedling regeneration) from the Forest Inventory Analysis program in conjunction with environmental data to model how these lineages respond to current and future climatic gradients. Ecologically meaningful relationships are explored in the intraspecific context of hemlock abundance distribution and then related to genetic variation. We also assess hemlock’s colonization likelihood via a long distance dispersal model and explore its future genetic and ecological conservation potential by combining the future suitable habitats with colonization likelihoods. Results show that future habitats under climate change will markedly decline for eastern hemlock. The remaining areas with higher habitat quality and colonization potential are confined to the SE, the genetic zone nearest the species’ putative glacial refugia, pointing to the need to focus our conservation efforts on this ecologically and genetically important region.     

Y DNA and mitochondrial lineages in European and Asian populations of the brown hare (Lepus europaeus)

Both the Cytb gene of mtDNA and Y chromosome markers were studied in a relatively large sample of brown hares (L. europaeus) from Europe and Anatolia (Turkey and Israel), together with other seven Lepus species, in order to enable comparative analysis of possible sex-specific gene flow. Furthermore, Y chromosome markers were compared with data from biparentally inherited markers in an attempt to understand whether or not their pattern of distribution was congruent with that of allozymes or whether they rather matched mtDNA phylogenies, with which they share uniparental inheritance. Consistent with the general observation, levels of interspecific genetic variability were very low for the Y chromosome markers compared with mtDNA. Moreover, lack of interspecific variation for the Y-DNA studied within Lepus genus rendered these markers improper for any further phylogenetic analysis. With the highest nucleotide diversity in Anatolia compared with Europe, both marker systems confirmed an unbroken species history in Anatolia, corroborated the hypothesis of continuous gene flow from Anatolia's neighbouring regions, and supported the idea of a quick postglacial colonization followed by expansion of the species in large parts of Europe. Phylogenetic analysis under mtDNA revealed the existence of four different haplogroups with a well defined distribution across Europe and Anatolia. Both genetic systems supported the deep separation of Anatolian and European lineages of L. europaeus. Nevertheless, Anatolian Y-DNA lineages extended across a longer geographic distance in south-eastern Europe than Anatolian mtDNA haplotypes, probably as a result of higher female philopatry that makes mtDNA introgression more difficult in brown hares.