Parasite infection reflects host genetic diversity among non-native populations of pumpkinseed sunfish in Europe

Species introductions often coincide with loss of genetic diversity and natural enemies. Anthropogenic translocation of the North-American pumpkinseed Lepomis gibbosus (L., 1758) (Centrarchidae) and its further spread have resulted in recent species establishment in most European countries. This study determines genetic differentiation of non-native European pumpkinseed populations and identifies how their genetic structure relates to the distribution and abundance of parasite species. Microsatellite analysis indicated presence of three genetic lineages, which were well supported by discriminant analysis based on parasite abundance data. The first lineage clustered pumpkinseed populations from northern and southern France and showed high allelic richness, heterozygosity and parasite richness. The second included populations along the “Southern invasion corridor” connecting the rivers Rhine, Main and Danube. The fish exhibited low to high genetic and parasite diversity and generally high parasite abundance. The third lineage clustered populations with low genetic and parasite diversity, located in Portuguese reservoirs and water bodies along the upper Elbe. Parasite species richness was significantly associated with host microsatellite heterozygosity and allelic richness, a trend partially affected by richness of North-American parasites. Furthermore, our results indicate that parasite community composition may serve as a useful biological tool to discriminate non-native fish populations and their inter-relationships.

     

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.     

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.     

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.     

Phylogeography and postglacial dispersal of arctic charr Salvelinus alpinus in North America

Restriction fragment length polymorphism analysis of mitochondrial DNA (mtDNA) was used to reconstruct postglacial dispersal routes of arctic charr Salvelinus alpinus in North America. Twelve of 35 restriction enzymes detected polymorphisms among representative populations, revealing two distinct lineages with an estimated nucleotide divergence of 1.32%. Subsequent screening of 869 fish from 54 populations with four diagnostic restriction enzymes showed that these lineages have largely allopatric distributions, suggesting their dispersal from separate northern and eastern glacial refugia. In addition, geographical and genetic structure among eastern populations suggested the existence of a second eastern refuge. Among the three lineages, the most divergent (Arctic) lineage occurred from Alaska east to northern Labrador. Quebec, New Brunswick, and New England were colonized by a second (Laurentian) lineage, and Labrador by a third group. Contact between refugial groups was only detected in two Labrador populations. The Arctic lineage was highly differentiated from eastern North American and European haplotypes, and probably diverged during the early Pleistocene. By contrast, the Laurentian and Labrador groups were similar to Old World charr, suggesting a shared ancestry during the mid-Pleistocene. In addition, the close relationship between Labrador and Laurentian charr indicates their probable divergence during the Wisconsinan glaciation.     

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.     

Lineage admixture during postglacial range expansion is responsible for the increased gene diversity of Kalopanax septemlobus in a recently colonised territory

We aimed to reveal the effects of range expansion and subsequent lineage admixture from separated glacial refugia on genetic diversity of Kalopanax septemlobus in Japan, by combining nuclear microsatellite data and ecological niche modelling. Allelic richness and gene diversity were compared at the population and regional level. We also statistically examined these indices as a function of population accessibility to the last glacial maximum (LGM) palaeodistribution reconstructed by ecological niche modelling to test a simple range expansion scenario from glacial refugia. Genetic diversity was highest in the populations of southern Japan and gradually decreased towards the north. However, an additional centre of genetic diversity, when measured as gene diversity, was found in northern Honshu Island, where distinct lineages were shown to be in contact. Positive effects of population accessibility to the LGM range were detected in both diversity indices at different spatial scales. The combined data support independent postglacial range expansions towards the north from the edge populations on the exposed coastal shelf of Pacific and Sea of Japan in northern Honshu during the LGM, which subsequently resulted in markedly low genetic diversity in the northernmost extant range, Hokkaido. The regional increase in gene diversity in northern Honshu is likely to be the result of postglacial lineage admixture. Relative difference in the spatial scales best relating population genetic diversity with the LGM distribution can be explained by a higher rate of allelic richness diversity loss during range expansions and stronger effects of lineage admixture on gene diversity.     

Contrasting patterns of mitochondrial DNA and microsatellite introgressive hybridization between lineages of lake whitefish (Coregonus clupeaformis); relevance for speciation

We performed a combined analysis of mitochondrial DNA (mtDNA) and microsatellite loci among lake whitefish (Coregonus clupeaformis) populations in order to assess the levels of congruence between both types of markers in defining patterns of genetic structuring, introgressive hybridization and inferring population origins in the hybrid zone of the St. John River basin. A second objective was to test the hypothesis that secondary contact between glacial lineages always resulted in the occurrence of sympatric dwarf and normal whitefish ecotypes. Fish were sampled from 35 populations and polymorphism was screened at mtDNA and six microsatellite loci for a total of 688 and 763 whitefish, respectively. Four lakes harbouring a single whitefish population of normal ecotype admixed with mtDNA haplotypes of different lineages were found. This confirmed that secondary contact between whitefish evolutionary lineages did not always result in the persistence of reproductively isolated ecotypes. Microsatellites further supported the definition of distinct glacial lineages by identifying lineage-specific allelic size groups. They also further supported the hypothesis that ecotypes originated from either a single founding lineage (sympatric divergence) or following secondary contacts between lineages (allopatric divergence), depending on the lake. In general, however, the pattern of population differentiation and introgressive hybridization observed at microsatellites was in sharp contrast with that depicted by mtDNA variation. Both factorial correspondence analysis and analysis of admixture proportion revealed a much more pronounced pattern of introgressive hybridization than depicted by mtDNA analyses. Variable levels of introgression indicated that environmental differences may be as important as the historical contingency of secondary contact in explaining the persistence of sympatric ecotypes and the differential pattern of introgressive hybridization among lakes. Whitefish populations from the St. John River basin hybrid zone represent a rare illustration of a continuum of both morphological and genetic differentiation within a given taxon, spanning from complete introgression to possibly complete reproductive isolation, depending on lakes. Thus, each lake may be viewed as a different temporal snapshot taken throughout the gradual process of speciation.     

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.     

Three divergent lineages within an Australian marsupial (Petrogale penicillata) suggest multiple major refugia for mesic taxa in southeast Australia

Mesic southeastern Australia represents the continent's ancestral biome and is highly biodiverse, yet its phylogeographic history remains poorly understood. Here, we examine mitochondrial DNA (mtDNA) control region and microsatellite diversity in the brush‐tailed rock‐wallaby (Petrogale penicillata; n = 279 from 31 sites), to assess historic evolutionary and biogeographic processes in southeastern Australia. Our results (mtDNA, microsatellites) confirmed three geographically discrete and genetically divergent lineages within brush‐tailed rock‐wallabies, whose divergence appears to date to the mid‐Pleistocene. These three lineages had been hypothesized previously but data were limited. While the Northern and Central lineages were separated by a known biogeographic barrier (Hunter Valley), the boundary between the Central and Southern lineages was not. We propose that during particularly cool glacial cycles, the high peaks of the Great Dividing Range and the narrow adjacent coastal plain resulted in a more significant north–south barrier for mesic taxa in southeastern Australia than has been previously appreciated. Similarly, located phylogeographic breaks in codistributed species highlight the importance of these regions in shaping the distribution of biodiversity in southeastern Australia and suggest the existence of three major refuge areas during the Pleistocene. Substructuring within the northern lineage also suggests the occurrence of multiple local refugia during some glacial cycles. Within the three major lineages, most brush‐tailed rock‐wallaby populations were locally highly structured, indicating limited dispersal by both sexes. The three identified lineages represent evolutionarily significant units and should be managed to maximize the retention of genetic diversity within this threatened species.     

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.     

Phylogeographical lineages of Arctic grayling (Thymallus arcticus) in North America: divergence, origins and affinities with Eurasian Thymallus

The number and location of Arctic glacial refugia utilized by taxa during the Pleistocene are continuing uncertainties in Holarctic phylogeography. Arctic grayling (Thymallus arcticus) are widely distributed in freshwaters from the eastern side of Hudson Bay (Canada) west to central Asia. We studied mitochondrial DNA (mtDNA) and microsatellite DNA variation in North American T. arcticus to test for genetic signatures of survival in, and postglacial dispersal from, multiple glacial refugia, and to assess their evolutionary affinities with Eurasian Thymallus. In samples from 32 localities, we resolved 12 mtDNA haplotypes belonging to three assemblages that differed from each other in sequence by between 0.75 and 2.13%: a 'South Beringia' lineage found from western Alaska to northern British Columbia, Canada; a 'North Beringia' lineage found on the north slope of Alaska, the lower Mackenzie River, and to eastern Saskatchewan; and a 'Nahanni' lineage confined to the Nahanni River area of the upper Mackenzie River drainage. Sequence analysis of a portion of the control region indicated monophyly of all North American T. arcticus and their probable origin from eastern Siberian T. arcticus at least 3 Mya. Arctic grayling sampled from 25 localities displayed low allelic diversity and expected heterozygosity (H(E)) across five microsatellite loci (means of 2.1 alleles and 0.27 H(E), respectively) and there were declines in these measures of genetic diversity with distance eastward from the lower Yukon River Valley. Assemblages defined by mtDNA divergences were less apparent at microsatellite loci, but again the Nahanni lineage was the most distinctive. Analysis of molecular variance indicated that between 24% (microsatellite DNA) and 81% (mtDNA) of the variance was attributable to differences among South Beringia, North Beringia and Nahanni lineages. Our data suggest that extant North American Arctic grayling are more diverse phylogeographically than previously suspected and that they consist of at least three major lineages that originated in distinct Pleistocene glacial refugia. T. arcticus probably originated and dispersed from Eurasia to North America in the late to mid-Pliocene, but our data also suggest more recent (mid-late Pleistocene) interactions between lineages across Beringia.     

Colonization history of north European field voles (Microtus agrestis) revealed by mitochondrial DNA

The genetic structure of field vole (Microtus agrestis) populations from northern Europe was examined by restriction fragment length polymorphisms of mitochondrial DNA (mtDNA) in 150 individuals from 67 localities. A total of 83 haplotypes was observed, most of which were rare and highly localized geographically. Overall nucleotide diversity was high (134%), but showed a tendency to decrease with higher latitude. Two major mtDNA lineages differing by 2% in nucleotide sequence were identified. A southern mtDNA lineage was observed in field voles from Britain, Denmark and southern and central Sweden, whereas voles from Finland and northern Sweden belonged to a northern lineage. The strict phylogeographic pattern suggests that the present population generic structure in field voles reflects glacial history: the two groups are derived from different glacial refugia, and recolonized Fennoscandia from two directions. A 150–200-km-wide secondary contact zone between the two mtDNA groups was found in northern Sweden. Distinct phylogeographic substructuring was observed within both major mtDNA groups.     

Maintenance of an endemic lineage of brown trout (Salmo trutta) within the Duero river basin

The Iberian Peninsula contains diverse populations of freshwater fish, with major river basins comprising differentiated biogeographic units. The Duero River flows through the North‐Western Iberian Peninsula and is one of the most important rivers within the Iberian glacial refuge. Brown trout (Salmo trutta) populate this whole basin, and studies using both allozyme and microsatellite loci have detected a geographically sorted distribution of genetic variation in this species. In this work, sequences of the mitochondrial control region obtained from 299 brown trout from the Duero River were compared with other Iberian and European datasets. Two differentiated haplotype groups were detected inside the Duero River basin. One of them was related to the Atlantic (AT) lineage that is present in Northern European populations, whereas the other comprised an unique group that was restricted to the inner region of the basin. The amount of divergence of this Duero group from the other brown trout populations studied is consistent with a new trout lineage (Duero, DU) that is endemic to this river basin and that diverged from other Atlantic populations during the Pleistocene. The distribution of the DU and AT quaternary lineages in the Duero River was consistent with the ichthyological pattern described in the basin that originated during the Miocene–Pliocene. Evidence of selective processes that favour the haplotypes of the DU lineage may explain this discrepancy.     

Genetic spatial structure of European common hamsters (Cricetus cricetus)--a result of repeated range expansion and demographic bottlenecks

The spatial genetic structure of common hamsters (Cricetus cricetus) was investigated using three partial mitochondrial (mt) genes and 11 nuclear microsatellite loci. All marker systems revealed significant population differentiation across Europe. Hamsters in central and western Europe belong largely to two allopatric mitochondrial lineages south and northwest of the Carpathian and Sudetes. The southern group, 'Pannonia', comprises populations inside the Carpathian basin (Czech Republic, Hungary) while the second group, 'North', includes hamsters from Belgium, the Netherlands, France, and Germany. Isolation of the lineages is maintained by a combination of geographical and ecological barriers. Both main phylogeographical groups show signs of further subdivision. North is separated into highly polymorphic central German and less polymorphic western populations, which most likely split during late glacial expansion (15,000-10,000 bp). Clock estimates based on haplotype distributions predict a divergence of the two major lineages 85,000-147,000 bp. Expansion times fall during the last glaciation (115,000-10,000 bp) corroborating fossil data, which identify Cricetus cricetus as characteristic of colder climatic phases. Despite the allopatry of mt haplotypes, there is an overlap of nuclear microsatellite alleles between phylogeographical units. Although there are strong evidence that Pannonian hamsters have persisted inside the Carpathian basin over the last 50,000 years, genetic differentiation among European hamsters has mainly been caused by immigration from different eastern refugia. Possible source populations are likely to be found in the Ukrainian and the southern Russian plains--core areas of hamster distribution. From there, hamsters have repeatedly expanded during the Quaternary.     

Genetic differentiation of European grayling populations across the Main, Danube and Elbe drainages in Bavaria

Analysis of mitochondrial ( ND-1/3/4 genes) and nuclear ( GH-1 gene, four microsatellite loci) DNA markers of European grayling Thymallus thymallus populations identified strong genetic differentiation between the Rhine/Main, Elbe and Danube drainages in Bavaria, as a result of both present processes and past history. The Danube and the Main-Elbe group diverged about five times earlier than the populations of Main and Elbe. These data suggest that exchange and transfer of grayling stocking material between these drainages should be avoided, to maintain the genetic diversity and integrity of populations.     

Loss of genetic variability in reintroduced roach (Rutilus rutilus) populations

Genetic variation at five microsatellite loci and in mtDNA was surveyed in reintroduced and 'control' populations of roach ( Rutilus rutilus ) in Sweden. Microsatellite allelic richness and allele size ranges were significantly reduced in reintroduced populations, and mtDNA diversity was nearly significantly reduced in reintroduced populations. These measures of genetic variability were strongly correlated with lake characteristics that influence population size and food availability.     

Genetic structure in Orchesella cincta (Collembola): strong subdivision of European populations inferred from mtDNA and AFLP markers

Population genetic structure is determined both by current processes and historical events. Current processes include gene flow, which is largely influenced by the migration capacity of a species. Historical events are, for example, glaciation periods, which have had a major impact on the distribution of many species. Species with a low capacity or tendency to move about or disperse often exhibit clear spatial genetic structures, whereas mobile species mostly show less spatial genetic differentiation. In this paper we report on the genetic structure of a small, wingless arthropod species (Orchesella cincta: Collembola) in Europe. For this purpose we used mtDNA COII sequences and AFLP markers. We show that large genetic differences exist between populations of O. cincta, as expected from O. cincta's winglessness and sedentary lifestyle. Despite the fact that most variability was observed within populations (59%), a highly significant amount of AFLP variation (25%) was observed between populations from northwestern Europe, central Europe and Italy. This suggests that gene flow among regions is extremely low, which is additionally supported by the lack of shared mtDNA alleles between regions. Based on the genetic variation and sequence differences observed we conclude that the subdivision occurred long before the last glaciation periods. Although the populations still interbreed in the lab, we assume that in the long term the genetic isolation of these regions may lead to speciation processes.     

Global major histocompatibility Class II β (mh-IIβ)-polymorphism in Arctic charr Salvelinus alpinus

This study explored the use of the gene encoding the β subunit of the major histocompatibility (MH) receptor as a population marker in Arctic charr Salvelinus alpinus. The use of this polymorphic marker allowed differentiation of the S. alpinus lineages previously defined using mitochondrial DNA (mtDNA) but also allowed differentiation between the populations studied within those lineages. The majority of the variation observed here occurred prior to the last glaciation event. Nevertheless, all S. alpinus populations were differentiated using both MH Class II β (mh-IIβ) sequences and allelic frequencies. The fact that all the populations studied presented high rates of non-synonymous: synonymous substitutions and high levels of interpopulation variation, suggested mh-IIβ as an ideal marker to assess differentiation among S. alpinus populations in ways that may represent divergence both by genetic drift and natural adaptation to the local environment.     

Mitochondrial D-loop phylogeny signals two native Iberian red deer (Cervus elaphus) Lineages genetically different to Western and Eastern European red deer and infers human-mediated translocations

Native red deer (Cervus elaphus) in Western Europe might at least partially derive from refugial populations which survived in the Iberian Peninsula during the last glacial maximum, and that expanded northwards at the onset of the Holocene. However, the phylogeny and genetic structure of red deer populations in the Iberian Peninsula are still poorly known. This study was planned, in a first step, to reconstruct the phylogenetic relationship of the main red deer populations extant in Spain by the analyses of an extensive sample of mitochondrial DNA sequences. Results indicate that sequences from these populations can be assigned to one of two deeply divergent mtDNA lineages (South-Western and Central-Eastern) with molecular divergence nearby the 2 %. In each lineage were respectively found sixteen and thirteen different haplotypes. It was evidenced that they may be allopatrically distributed in Spain with 86.6 % sequences of the South-Western lineage at the South-Western side and the 65 % sequences of Central-Eastern lineage in the Central-Eastern side. These mitochondrial lineages might have originated in two distinct refugial populations during the last glacial maximum. Genetic data also reveal instances of admixture between native populations and translocated European red deer, which belong to at least three distinct subspecies. Gene introgression was mainly due to red deer from Western European populations. The genetic contribution of red deer translocated from Eastern Europe (C. e. hippelaphus) or North Africa (C. e. corsicanus, C. e. barbarus) was apparently less deep. The extant phylogenetic relationship and evidences of genetic admixture suggest that sound conservation actions for the native Iberian red deer should severely restrict the introduction of alien red deer and, when possible, avoid admixture between the South-Western and Central-Eastern mtDNA lineages.