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Maria Ogielska - One of the best experts on this subject based on the ideXlab platform.
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the programmed dna elimination and formation of micronuclei in germ line cells of the natural hybridogenetic water frog Pelophylax esculentus
Scientific Reports, 2018Co-Authors: Magdalena Chmielewska, Dmitry Dedukh, Katarzyna Haczkiewicz, Beata Rozenblutkościsty, Mikolaj Kaźmierczak, Krzysztof Kolenda, Ewa Serwa, Agnieszka Pietraslebioda, Alla Krasikova, Maria OgielskaAbstract:DNA elimination is a radical form of gene silencing and occurs both in somatic and germ cells. The programmed DNA elimination occurs during gametogenesis in interspecies hybrids that reproduce by hybridogenesis (stick insects, fishes, and amphibians) and concerns removal of whole genomes of one of the parental species and production of clonal gametes propagating the genome of the other species. The cellular mechanisms differ considerably in hybridogenetic insects and fishes but remains unknown in edible frogs Pelophylax esculentus, natural hybrids between Pelophylax lessonae and Pelophylax ridibundus. Here we report DNA elimination mechanism in early developing gonads of diploid and triploid hybrid frogs, studied by TEM, immunofluorescence, and cytochemistry. In gonocytes of both sexes (primary oogonia and prespermatogonia), micronuclei emerge as detached nuclear buds formed during interphase. We found depletion of nuclear pore complexes in micronuclear membrane and chromatin inactivation via heterochromatinization followed by degradation of micronuclei by autophagy. Micronuclei formation does not lead to apoptotic cell death showing that genome elimination is a physiological process. Chromatin elimination via micronuclei in P. esculentus is unique among hybridogenetic animals and contributes to broadening the knowledge about reproductive modes in animals.
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Batrachochytrium dendrobatidis is present in Poland and associated with reduced fitness in wild populations of Pelophylax lessonae
Diseases of Aquatic Organisms, 2017Co-Authors: Krzysztof Kolenda, Maria Ogielska, Anna Najbar, Vojtech BaláAbstract:The fungus Batrachochytrium dendrobatidis (Bd) is a pathogen associated with global declines of amphibians. We used qPCR to detect Bd in 255 samples from 10 Polish populations of 8 species. We found Bd infection in 3 species (Bombina variegata, Pelophylax lessonae, P. esculentus). The infection intensity in P. lessonae reached a maximum of 58400 genomic equivalents of zoospores (GE), and the 2 most heavily infected individuals died. Previous observations of the populations that included infected individuals showed reduced body size, failure to reproduce, and mortalities of adults. These data highlight the importance of emerging diseases, and the need to recognize them as an important factor in conservation of the genus Pelophylax in Poland and Central and Eastern Europe.
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preliminary genetic data suggest the occurrence of the balkan water frog Pelophylax kurtmuelleri in southwestern poland
Amphibia-reptilia, 2017Co-Authors: Krzysztof Kolenda, Sebastian Hofman, Maria Ogielska, Agnieszka Pietraslebioda, Maciej PabijanAbstract:Recent molecular studies have detected the occurrence of exotic water frog species ( Pelophylax sp.) in central and western European populations. Here, we report genetic evidence for the occurrence of the Balkan water frog, Pelophylax kurtmuelleri , in southwestern Poland. We found a high frequency of an allele of serum albumin intron-1 and a mitochondrial cytochrome b haplotype specific for this southern taxon in frogs from the Barycz river drainage system. We interpret this finding as evidence of admixture between P. kurtmuelleri and the local ridibundus-esculentus water frog population. The origin of the exotic P. kurtmuelleri mitochondrial and nuclear alleles in southwestern Poland could be due to (i) hybridization after a human-mediated introduction of P. kurtmuelleri , (ii) the persistence of ancestral polymorphism in central European P. ridibundus , or (iii) hybridization between P. kurtmuelleri and P. ridibundus in the Balkans followed by the northward expansion of admixed P. ridibundus . Identical mtDNA haplotypes found in southwestern Poland and localities on the borders between Greece, Albania and Macedonia suggest that this region harboured the source population of P. kurtmuelleri at the studied site.
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Genome dosage effect and colouration features in hybridogenetic water frogs of the Pelophylax esculentus complex
Amphibia-reptilia, 2013Co-Authors: Piotr Kierzkowski, Piotr Kosiba, Mariusz Rybacki, Małgorzata Socha, Maria OgielskaAbstract:There are three taxons of central European water frogs of the Pelophylax esculentus complex: two morphologically distinct species, Pelophylax lessonae (LL) and Pelophylax ridibundus (RR), and hybrids Pelophylax esculentus, which can be either diploid (RL) or triploid (LLR or RRL). The morphology of hybrids is supposed to follow genome dosage effect. We describe colouration of water frogs with genome composition verified by chromosome analysis. Typical colouration features in LL were: spots on the ventral side, brown limbs, “weak” femur spotting pattern, brown dorsal folds and yellow-green colour in “waist”. Typical RR had dark-green or olive-green limbs, “full” femur spotting pattern, no hip spot and no yellow colour in “waist”. For all hybrids the most typical features were strong spots on the ventral side and a mosaic of green and brown colour on limbs. Typical LLR had brown-greenish dorsal folds underlined by a partial black line, “weak” femur spotting pattern and yellow-greenish colour in “waist” and on femur. Typical RL had greenish hind limbs, green dorsal folds, no yellow colour in “waist”, and no hip spot. Typical RRL was similar to RL, but had a continuous black line under dorsal folds. There were, however, numerous exceptions to these trends, with the most prominent being much higher than expected variability of colouration of Pelophylax lessonae. Therefore caution must be advised when trying to estimate genome composition of water frogs solely on the basis of colouration.
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a simplified molecular method for distinguishing among species and ploidy levels in european water frogs Pelophylax
Molecular Ecology Resources, 2012Co-Authors: Susanne J Hauswaldt, Ditte G Christiansen, Maria Ogielska, Daria Dziewulskaszwajkowska, Manuela Hoer, Elżbieta Czernicka, Miguel VencesAbstract:Western Palearctic water frogs in the genus Pelophylax are a set of morphologically similar anuran species that form hybridogenetic complexes. Fully reliable identification of species and especially of hybrid ploidy depends on karyological and molecular methods. In central Europe, native water frog populations consist of the Pelophylax esculentus complex, that is, P. lessonae (LL), P. ridibundus (RR) and the hybrid form P. esculentus that can have different karyotypes (RL, LLR and RRL). We developed existing molecular methods further and propose a simple PCR method based on size-differences in the length of the serum albumin intron-1 and the RanaCR1, a non-LTR retrotransposon of the chicken repeat (CR) family. This PCR yields taxon-specific banding patterns that can easily be screened by standard agarose gel electrophoresis and correctly identify species in all of the 160 samples that had been identified to karyotype with other methods. To distinguish ploidy levels in LR, LLR and RRL specimens, we used the ratio of the peak heights of the larger (ridibundus specific) to the smaller (lessonae specific) bands of fluorescently labelled PCR products resolved on a capillary DNA sequencer and obtained a correct assignment of the karyotype in 93% of cases. Our new method will cut down time and expenses drastically for a reliable identification of water frogs of the P. esculentus complex and potentially for identification of other hybridogenetic complexes and/or taxa, and it even serves as a good indicator of the ploidy status of hybrid individuals.
Sylvain Dubey - One of the best experts on this subject based on the ideXlab platform.
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Invasion genomics supports an old hybrid swarm of pool frogs in Western Europe
Biological Invasions, 2020Co-Authors: Christophe Dufresnes, Sylvain DubeyAbstract:Genomic tools like RAD-sequencing can provide the resolution to understand the complex genetic patterns underlying cryptic biological invasions. Here we use this method to clarify the genetic consequences of a rampant invasion by the Italian pool frog ( Pelophylax bergeri ) north of the Alps, threatening the native P. lessonae and its hybridogenetic hybrid P. esculentus . Patterns of genetic structure were consistent with massive genetic introgression, except for an isolated mountain valley in Switzerland (Joux). Moreover, alien alleles also reached the hybridogens, which should be considered non-native as well. Potentially initiated during antic times, this hybrid swarm likely extends all over W-Europe and rises among the largest amphibian invasions documented on the old continent. Invasion genomics thus hold great promises to reliably inform conservationists, especially in animal groups for which conventional genetic markers may not always be diagnostic between closely-related, morphologically similar species.
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population genomics of an exceptional hybridogenetic system of Pelophylax water frogs
BMC Evolutionary Biology, 2019Co-Authors: Sylvain Dubey, Tiziano Maddalena, Laura Bonny, Daniel L Jeffries, Christophe DufresnesAbstract:Hybridogenesis can represent the first stage towards hybrid speciation where the hybrid taxon eventually weans off its parental species. In hybridogenetic water frogs, the hybrid Pelophylax kl. esculentus (genomes RL) usually eliminates one genome from its germline and relies on its parental species P. lessonae (genomes LL) or P. ridibundus (genomes RR) to perpetuate in so-called L-E and R-E systems. But not exclusively: some all-hybrid populations (E-E system) bypass the need for their parental species and fulfill their sexual cycle via triploid hybrid frogs. Genetic surveys are essential to understand the great diversity of these hybridogenetic dynamics and their evolution. Here we conducted such study using RAD-sequencing on Pelophylax from southern Switzerland (Ticino), a geographically-isolated region featuring different assemblages of parental P. lessonae and hybrid P. kl. esculentus. We found two types of hybridogenetic systems in Ticino: an L-E system in northern populations and a presumably all-hybrid E-E system in the closely-related southern populations, where P. lessonae was not detected. In the latter, we did not find evidence for triploid individuals from the population genomic data, but identified a few P. ridibundus (RR) as offspring from interhybrid crosses (LR × LR). Assuming P. lessonae is truly absent from southern Ticino, the putative maintenance of all-hybrid populations without triploid individuals would require an unusual lability of genome elimination, namely that P. kl. esculentus from both sexes are capable of producing gametes with either L or R genomes. This could be achieved by the co-existence of L- and R- eliminating lineages or by “hybrid amphigamy”, i. e. males and females producing sperm and eggs among which both genomes are represented. These hypotheses imply that polyploidy is not the exclusive evolutionary pathway for hybrids to become reproductively independent, and challenge the classical view that hybridogenetic taxa are necessarily sexual parasites.
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multiple uprising invasions of Pelophylax water frogs potentially inducing a new hybridogenetic complex
Scientific Reports, 2017Co-Authors: Christophe Dufresne, Mathieu Denoel, Lionel Di Santo, Sylvain DubeyAbstract:The genetic era has revolutionized our perception of biological invasions. Yet, it is usually too late to understand their genesis for efcient management. Here, we take the rare opportunity to reconstruct the scenario of an uprising invasion of the famous water frogs (Pelophylax) in southern France, through a fne-scale genetic survey. We identifed three diferent taxa over less than 200 km2: the autochthonous P. perezi, along with the alien P. ridibundus and P. kurtmuelleri, which have suddenly become invasive. As a consequence, the latter hybridizes and may now form a novel hybridogenetic complex with P. perezi, which could actively promote its replacement. This exceptional situation makes a textbook application of genetics to early-detect, monitor and understand the onset of biological invasions before they pose a continental-wide threat. It further emphasizes the alarming rate of amphibian translocations, both at global and local scales, as well as the outstanding invasive potential of Pelophylax aliens.
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Cryptic invasion of Italian pool frogs (Pelophylax bergeri) across Western Europe unraveled by multilocus phylogeography
Biological Invasions, 2017Co-Authors: Christophe Dufresnes, Johan Schuerch, Glib Mazepa, Daniele Canestrelli, James Leuenberger, N. Grandjean, Nicolas Perrin, Loredana Santo, Sylvain DubeyAbstract:Human introductions of exotic amphibians can have catastrophic effects on native species. However, they usually remain unnoticed without genetic tools when species are difficult to distinguish morphologically. In Western Europe, pool frogs (Pelophylax sp.) make a worrisome case: recent genetic data showed the presence of Italian (Pelophylax bergeri) mtDNA haplotypes within the range of the threatened European Pelophylax lessonae, two morphologically similar taxa. Here we conduct a multilocus phylogeographic and population genetic survey of European and Italian pool frogs (combining present and historic samples), to investigate the origin(s) and consequences of potential introductions. Results are unequivocal: we show that the alien P. bergeri have extensively invaded France and north-Alpine Switzerland, and have also deeply introgressed with P. lessonae, which has led to the complete replacement of most populations. Alien specimens have probably been translocated multiple times from Central Italy at least prior to the 1960s. Based on our dense sampling, only two areas, north and south of the Alps still host native pool frogs in Switzerland, the Joux Valley near the French border and the canton of Ticino, respectively. Importantly, we show that these last P. lessonae populations are remnants of a private genetic diversity specific to Western Europe, which vanished during the P. bergeri's invasion. Our study emphasizes the risk of genetic pollution during invasion by human-introduced taxa and brings alarming concern regarding uncontrolled amphibian translocations. Moreover, it demonstrates the necessity for genetic surveys to detect and monitor these invasions, especially where species determination is problematic.
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multiple origins of invasive and native water frogs Pelophylax spp in switzerland
Biological Journal of The Linnean Society, 2014Co-Authors: Sylvain Dubey, Julien Leuenberger, Nicolas PerrinAbstract:The marsh frog (Pelophylax ridibundus) has been introduced in many areas in Central and Western Europe as a result of commercial trade with Eastern Europe, and is rapidly replacing the native pool frog (P. lessonae). A large number of Pelophylax species are distributed in Eastern Europe and the strong phenotypic similarity between these species is rendering their identification hazardous. Consequently, alien populations of Pelophylax might not strictly be composed of P. ridibundus as previously suspected. In the present study, we analysed the cytochrome-b and NADH dehydrogenase subunit 3 genes of introduced and native Pelophylax species from Switzerland (299 individuals) in order to properly identify the source populations of the invaders and the genetic status of the native species. Our study highlighted the occurrence of several genetic lineages of invasive frogs in western Switzerland. Unexpectedly, we also showed that several populations of the native pool frog (P. lessonae) cluster with the Italian pool frog P. bergeri from central Italy (considered by some authors as a subspecies of P. lessonae). Hence, these populations are probably also the result of introductions, meaning that the number of native P. lessonae populations is fewer than expected in Switzerland. These findings have important implications concerning the conservation of the endemic pool frog populations, as the presence of multiple alien species could strongly affect their long-term subsistence. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112, 442–449.
Peter Mikulicek - One of the best experts on this subject based on the ideXlab platform.
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taxonomic composition and ploidy level among european water frogs anura ranidae Pelophylax in eastern hungary
Journal of Zoological Systematics and Evolutionary Research, 2017Co-Authors: David Herczeg, Judit Voros, Ditte G Christiansen, Michal Benovics, Peter MikulicekAbstract:The western Palaearctic water frogs in the genus Pelophylax comprise several distinct species and three hybridogenetic hybrid forms. In this study, we focus on the Pelophylax esculentus complex, which consists of two sexual species, Pelophylax ridibundus and Pelophylax lessonae, and their hybridogenetic hybrid, Pelophylax esculentus. Specifically, we investigated taxonomic composition and ploidy level of water frogs sampled in three different types of wetland habitats in the Hortobagy National Park (HNP), eastern Hungary. Using variation in serum albumin intron 1 (SAI-1) and 15 microsatellite loci, we detected the presence of all members of the P. esculentus complex in the studied localities. In one locality, all three taxa occurred syntopically, while in others water frog populations consisted of P. ridibundus and P. esculentus exclusively. The genomic composition of the 63 examined hybrid specimens analysed with microsatellites showed the occurrence of diploid genotypes only. We used a population genetic approach (allelic richness, gene diversity, multilocus genotypes and multilocus disequilibrium) to infer the breeding system of water frogs at HNP. Our data indicate that at least in two populations, hybrids form gametes with clonally transmitted P. ridibundus genome and produce a new hybrid generation by mating with P. lessonae.
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Population structure and reproductive modes of hybridogenetic water frogs (Pelophylax esculentus complex) in Slovakia
2017Co-Authors: Peter Mikulicek, Michal Benovics, Matej KautmanAbstract:Pelophylax esculentus complex consists of two parental species P. ridibundus and P. lessonae, whose primary hybridization leads to hybridogenetic diploid and triploid lineages of P. esculentus. Hybrids clonally transmit one parental genome and mate with the other parental species. In Slovakia, we found syntopic occurrence of diploid and triploid hybrids with P. lessonae, syntopic occurrence of all three taxa as well as the existence of pure P. ridibundus populations. All triploids are exclusively males possessing one ridibundus and two different lessonae genomes. Irrespective of the population composition, diploids produce ridibundus gametes; triploid males produce diploid lessonae sperms.
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Genetic diversity of Pelophylax species in south-western Balkans
2017Co-Authors: Michal Benovics, Daniel Jablonski, Peter MikulicekAbstract:Water frogs of the genus Pelophylax comprise 12 species and three asexual hybrid taxa in the western Palearctic. The continental part of the Balkan Peninsula is inhabited by five species, whose distribution is poorly known. Therefore, we decided to shed more light to diversity of these relatively common and widely distributed, but still overlooked amphibians in the Balkans. During years 2014 – 2017 we collected a total of 219 Pelophylax individuals from 85 localities across western and south-western Balkan Peninsula. We analyzed sequences of the mitochondrial ND2 gene and nuclear fragment for serum albumin intron-1 (SAI). Based on nuclear data the most of analyzed specimens were recognized as P. ridibundus. This species was found in Albania, Bosnia and Herzegovina, Croatia, Greece, FYROM, Montenegro and Serbia. Rest of specimens were assigned into P. epeiroticus, P. bedriagae and P. shqipericus. While P. epeiroticus was found in Greece and southern Albania, P. bedriagae was collected from Bosnia and Herzegovina only. Two individuals assigned to P. shqipericus were collected from southern Montenegro and north-western Albania. Analysis of mitochondrial diversity recognized 73 haplotypes (Hd: 0.931), while the majority of them were assigned to P. ridibundus (63), eight and two haplotypes were recognized in P. epeiroticus and P. shqipericus, respectively. The largest haplotype diversity was observed in southern and south-eastern Albania. We also observed occasional discrepancies between nuclear and mitochondrial signal, which could be attributed either to interspecies introgression of mitochondrial DNA or incomplete lineage sorting.
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genetic diversity and distribution patterns of diploid and polyploid hybrid water frog populations Pelophylax esculentus complex across europe
Molecular Ecology, 2015Co-Authors: Alexandra Hoffmann, Ditte G Christiansen, Peter Mikulicek, Lukas Choleva, Nicolas B M Pruvost, Jorg Plotner, Sandra Rothlisberger, Dan Cogălniceanu, Istvan Saskovacs, Dmitry ShabanovAbstract:Polyploidization is a rare yet sometimes successful way for animals to rapidly create geno- and phenotypes that may colonize new habitats and quickly adapt to environmental changes. In this study, we use water frogs of the Pelophylax esculentus complex, comprising two species (Pelophylax lessonae, genotype LL; Pelophylax ridibundus, RR) and various diploid (LR) and triploid (LLR, LRR) hybrid forms, summarized as P. esculentus, as a model for studying recent hybridization and polyploidization in the context of speciation. Specifically, we compared the geographic distribution and genetic diversity of diploid and triploid hybrids across Europe to understand their origin, maintenance and potential role in hybrid speciation. We found that different hybrid and parental genotypes are not evenly distributed across Europe. Rather, their genetic diversity is structured by latitude and longitude and the presence/absence of parental species but not of triploids. Highest genetic diversity was observed in central and eastern Europe, the lowest in the northwestern parts of Europe. This gradient can be explained by the decrease in genetic diversity during postglacial expansion from southeastern glacial refuge areas. Genealogical relationships calculated on the basis of microsatellite data clearly indicate that hybrids are of multiple origin and include a huge variety of parental genomes. Water frogs in mixed-ploidy populations without any parental species (i.e. all-hybrid populations) can be viewed as evolutionary units that may be on their way towards hybrid speciation. Maintenance of such all-hybrid populations requires a continuous exchange of genomes between diploids and triploids, but scenarios for alternative evolutionary trajectories are discussed.
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mode of hybridogenesis and habitat preferences influence population composition of water frogs Pelophylax esculentus complex anura ranidae in a region of sympatric occurrence western slovakia
Journal of Zoological Systematics and Evolutionary Research, 2015Co-Authors: Peter Mikulicek, Matej Kautman, Jan Kautman, Nicolas B M PruvostAbstract:Coexistence of sperm-dependent asexual hybrids with their sexual progenitors depends on genetic and ecological interactions between sexual and asexual forms. In this study, we investigate genotypic composition, modes of hybridogenetic gametogenesis and habitat preferences of European water frogs (Pelophylax esculentus complex) in a region of sympatric occurrence. Pelophylax esculentus complex comprises parental species P. ridibundus and P. lessonae, whose primary hybridization leads to hybridogenetic lineages of P. esculentus. Hybrids clonally transmit one parental genome and mate with the other parental species, forming a new generation of hybrids. In the region of western Slovakia, we found syntopic occurrence of diploid and triploid hybrids with P. lessonae, syntopic occurrence of all three taxa as well as the existence of pure P. ridibundus populations. All triploid hybrids were exclusively male possessing one ridibundus and two different lessonae genomes (RLL). Sex ratio in diploid hybrids was substantially female-biased. Irrespective of the population composition, diploid hybrids excluded the lessonae genome from their germ line and produced ridibundus gametes. Contrarily, RLL males unequivocally eliminated the ridibundus genome and produced diploid lessonae sperms. Perpetuation of RLL males in studied populations is most likely achieved by their mating with diploid hybrid females. The composition of water frog populations is also shaped by taxon-specific habitat preferences. While P. ridibundus preferred larger water bodies (gravelpits, fishery ponds, dead river arms), P. lessonae was most frequently found in marshes and smaller sandpits. Pelophylax esculentus occupied predominately similar habitats as its sexual host P. lessonae.
Christophe Dufresnes - One of the best experts on this subject based on the ideXlab platform.
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Invasion genomics supports an old hybrid swarm of pool frogs in Western Europe
Biological Invasions, 2020Co-Authors: Christophe Dufresnes, Sylvain DubeyAbstract:Genomic tools like RAD-sequencing can provide the resolution to understand the complex genetic patterns underlying cryptic biological invasions. Here we use this method to clarify the genetic consequences of a rampant invasion by the Italian pool frog ( Pelophylax bergeri ) north of the Alps, threatening the native P. lessonae and its hybridogenetic hybrid P. esculentus . Patterns of genetic structure were consistent with massive genetic introgression, except for an isolated mountain valley in Switzerland (Joux). Moreover, alien alleles also reached the hybridogens, which should be considered non-native as well. Potentially initiated during antic times, this hybrid swarm likely extends all over W-Europe and rises among the largest amphibian invasions documented on the old continent. Invasion genomics thus hold great promises to reliably inform conservationists, especially in animal groups for which conventional genetic markers may not always be diagnostic between closely-related, morphologically similar species.
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population genomics of an exceptional hybridogenetic system of Pelophylax water frogs
BMC Evolutionary Biology, 2019Co-Authors: Sylvain Dubey, Tiziano Maddalena, Laura Bonny, Daniel L Jeffries, Christophe DufresnesAbstract:Hybridogenesis can represent the first stage towards hybrid speciation where the hybrid taxon eventually weans off its parental species. In hybridogenetic water frogs, the hybrid Pelophylax kl. esculentus (genomes RL) usually eliminates one genome from its germline and relies on its parental species P. lessonae (genomes LL) or P. ridibundus (genomes RR) to perpetuate in so-called L-E and R-E systems. But not exclusively: some all-hybrid populations (E-E system) bypass the need for their parental species and fulfill their sexual cycle via triploid hybrid frogs. Genetic surveys are essential to understand the great diversity of these hybridogenetic dynamics and their evolution. Here we conducted such study using RAD-sequencing on Pelophylax from southern Switzerland (Ticino), a geographically-isolated region featuring different assemblages of parental P. lessonae and hybrid P. kl. esculentus. We found two types of hybridogenetic systems in Ticino: an L-E system in northern populations and a presumably all-hybrid E-E system in the closely-related southern populations, where P. lessonae was not detected. In the latter, we did not find evidence for triploid individuals from the population genomic data, but identified a few P. ridibundus (RR) as offspring from interhybrid crosses (LR × LR). Assuming P. lessonae is truly absent from southern Ticino, the putative maintenance of all-hybrid populations without triploid individuals would require an unusual lability of genome elimination, namely that P. kl. esculentus from both sexes are capable of producing gametes with either L or R genomes. This could be achieved by the co-existence of L- and R- eliminating lineages or by “hybrid amphigamy”, i. e. males and females producing sperm and eggs among which both genomes are represented. These hypotheses imply that polyploidy is not the exclusive evolutionary pathway for hybrids to become reproductively independent, and challenge the classical view that hybridogenetic taxa are necessarily sexual parasites.
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Cryptic invasion of Italian pool frogs (Pelophylax bergeri) across Western Europe unraveled by multilocus phylogeography
Biological Invasions, 2017Co-Authors: Christophe Dufresnes, Johan Schuerch, Glib Mazepa, Daniele Canestrelli, James Leuenberger, N. Grandjean, Nicolas Perrin, Loredana Santo, Sylvain DubeyAbstract:Human introductions of exotic amphibians can have catastrophic effects on native species. However, they usually remain unnoticed without genetic tools when species are difficult to distinguish morphologically. In Western Europe, pool frogs (Pelophylax sp.) make a worrisome case: recent genetic data showed the presence of Italian (Pelophylax bergeri) mtDNA haplotypes within the range of the threatened European Pelophylax lessonae, two morphologically similar taxa. Here we conduct a multilocus phylogeographic and population genetic survey of European and Italian pool frogs (combining present and historic samples), to investigate the origin(s) and consequences of potential introductions. Results are unequivocal: we show that the alien P. bergeri have extensively invaded France and north-Alpine Switzerland, and have also deeply introgressed with P. lessonae, which has led to the complete replacement of most populations. Alien specimens have probably been translocated multiple times from Central Italy at least prior to the 1960s. Based on our dense sampling, only two areas, north and south of the Alps still host native pool frogs in Switzerland, the Joux Valley near the French border and the canton of Ticino, respectively. Importantly, we show that these last P. lessonae populations are remnants of a private genetic diversity specific to Western Europe, which vanished during the P. bergeri's invasion. Our study emphasizes the risk of genetic pollution during invasion by human-introduced taxa and brings alarming concern regarding uncontrolled amphibian translocations. Moreover, it demonstrates the necessity for genetic surveys to detect and monitor these invasions, especially where species determination is problematic.
Maciej Pabijan - One of the best experts on this subject based on the ideXlab platform.
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preliminary genetic data suggest the occurrence of the balkan water frog Pelophylax kurtmuelleri in southwestern poland
Amphibia-reptilia, 2017Co-Authors: Krzysztof Kolenda, Sebastian Hofman, Maria Ogielska, Agnieszka Pietraslebioda, Maciej PabijanAbstract:Recent molecular studies have detected the occurrence of exotic water frog species ( Pelophylax sp.) in central and western European populations. Here, we report genetic evidence for the occurrence of the Balkan water frog, Pelophylax kurtmuelleri , in southwestern Poland. We found a high frequency of an allele of serum albumin intron-1 and a mitochondrial cytochrome b haplotype specific for this southern taxon in frogs from the Barycz river drainage system. We interpret this finding as evidence of admixture between P. kurtmuelleri and the local ridibundus-esculentus water frog population. The origin of the exotic P. kurtmuelleri mitochondrial and nuclear alleles in southwestern Poland could be due to (i) hybridization after a human-mediated introduction of P. kurtmuelleri , (ii) the persistence of ancestral polymorphism in central European P. ridibundus , or (iii) hybridization between P. kurtmuelleri and P. ridibundus in the Balkans followed by the northward expansion of admixed P. ridibundus . Identical mtDNA haplotypes found in southwestern Poland and localities on the borders between Greece, Albania and Macedonia suggest that this region harboured the source population of P. kurtmuelleri at the studied site.
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phylogenetic relationships among four new complete mitogenome sequences of Pelophylax amphibia anura from the balkans and cyprus
Mitochondrial DNA, 2016Co-Authors: Sebastian Hofman, Maciej Pabijan, Artur Osikowski, Spartak N Litvinchuk, Jacek M SzymuraAbstract:AbstractWe present the full-length mitogenome sequences of four European water frog species: Pelophylax cypriensis, P. epeiroticus, P. kurtmuelleri and P. shqipericus. The mtDNA size varied from 17,363 to 17,895 bp, and its organization with the LPTF tRNA gene cluster preceding the 12 S rRNA gene displayed the typical Neobatrachian arrangement. Maximum likelihood and Bayesian inference revealed a well-resolved mtDNA phylogeny of seven European Pelophylax species. The uncorrected p-distance for among Pelophylax mitogenomes was 9.6 (range 0.01–0.13). Most divergent was the P. shqipericus mitogenome, clustering with the “P. lessonae” group, in contrast to the other three new Pelophylax mitogenomes related to the “P. bedriagae/ridibundus” lineage. The new mitogenomes resolve ambiguities of the phylogenetic placement of P. cretensis and P. epeiroticus.
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Complete mitochondrial genome of the Greek marsh frog Pelophylax cretensis (Anura, Ranidae)
Mitochondrial DNA, 2014Co-Authors: Sebastian Hofman, Maciej Pabijan, Artur Osikowski, Jacek M SzymuraAbstract:AbstractWe sequenced the complete mitochondrial genome of the Greek marsh frog Pelophylax cretensis, a water frog species endemic to the island of Crete. The genome sequence was 17,829 bp in size, and the gene order and contents were identical to those of previously reported mitochondrial genomes of other water frog species. This is the first complete mitogenome (i.e. including control region) described for western Palaearctic water frogs.
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mitochondrial genome organization and divergence in hybridizing central european waterfrogs of the Pelophylax esculentus complex anura ranidae
Gene, 2012Co-Authors: Sebastian Hofman, Maciej Pabijan, Daria Dziewulskaszwajkowska, Jacek M SzymuraAbstract:Abstract Natural transfer of mitochondrial DNA has occurred between three western Palaearctic waterfrog taxa: Pelophylax lessonae, Pelophylax ridibundus and their hybridogenetic hybrid, Pelophylax kl. esculentus . The transfer is asymmetric with most P. kl. esculentus and approximately one third of all central European P. ridibundus having mtDNA derived from P. lessonae (L-mtDNA). We obtained complete nucleotide sequences of multiple mitochondrial genomes (15,376–78 bp without control regions) from all 3 taxa, including a P. ridibundus frog with introgressed L-mtDNA. The gene content and organization of the mitogenomes correspond to those typical of neobatrachians. Divergence between the mtDNAs of P. lessonae and P. ridibundus is high with an uncorrected p -distance of 11.9% across the entire mitogenome. However, the rate of nucleotide substitution depends on the degree of functional constraint with up to 30-fold differences in levels of divergence. In general, mitochondrial genes encoding the translational machinery evolve very slowly, whereas genes encoding polypeptides of the electron transport system, especially the ND genes, evolve rapidly. Only 25 of 211–213 observed amino acid replacements could be classified as radical and are therefore more likely to be exposed to selection. A disproportionately high number of amino acid substitutions has occurred in the ND4 , ND4L and cytb genes of the P. lessonae lineage (including 36% of all radical changes). In contrast to the interspecific divergence, nucleotide polymorphism within L- and R-mtDNA is very low: L-mtDNA haplotypes differed on average by only 19 nucleotides, while there was no variation within two mtDNAs derived from P. ridibundus . This is an expected finding considering that we have sampled a post-glacial expansion area. Moreover, the introgressed L-mtDNA on a P. ridibundus background differed from other L-mtDNAs by only a few substitutions, indicative of a very recent introgression event. We discuss our findings in the context of natural selection acting on L-mtDNA and its potential significance in cytonuclear epistasis.