Gametogenesis produces gametes as a piece of genetic information transmitted to the offspring. While during sexual reproduction, progeny inherits a mix of genetic material from both parents, asexually reproducing organisms transfer a copy of maternal or paternal DNA to the progeny clonally. Parthenogenetic, gynogenetic and hybridogenetic animals have developed various mechanisms of gametogenesis, however, their inheritance is not fully understood. Here, we focused on the inheritance of asexual gametogenesis in hybrid Pelophylax esculentus (RL), emerging after crosses of P. lessonae (LL) and P. ridibundus (RR). To understand the mechanisms of gametogenesis in hybrids, we performed three-generation experiments of sexual P. ridibundus females and hybrids from all-male hybrid populations. Using fluorescent in situ hybridization, micronuclei analysis, flow cytometry and genotyping, we found that most adult hybrid males simultaneously produced two types of clonal sperm. Also, most male tadpole progeny in two successive backcrossed generations simultaneously eliminated L and R parental genomes, while some progeny produced only one type of sperm. We hypothesize that the reproductive variability of males producing two kinds of sperm is an adaptive mechanism to reproduce in mixed populations with P. ridibundus and may explain the extensive distribution of the all-male lineage across the European River Basin.

• Klíčová slova
• Amphispermy, Crossing experiments, FISH., Male hybridogenesis, Micronuclei, Monospermic, Spermatogenesis,
• MeSH
• genotyp MeSH
• hybridizace genetická * MeSH
• hybridizace in situ fluorescenční MeSH
• nepohlavní rozmnožování * genetika   MeSH
• Rana esculenta genetika   MeSH
• Ranidae genetika   fyziologie   MeSH
• spermie fyziologie   MeSH
• typy dědičnosti genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Hybrid taxa from the genus Pelophylax can propagate themselves in a modified way of sexual reproduction called hybridogenesis ensuring the formation of clonal gametes containing the genome of only one parental (host) species. Pelophylax grafi from South-Western Europe is a hybrid composed of P. ridibundus and P. perezi genomes and it lives with a host species P. perezi (P-G system). Yet it is unknown, whether non-Mendelian inheritance is fully maintained in such populations. In this study, we characterize P. perezi and P. grafi somatic karyotypes by using comparative genomic hybridization, genomic in situ hybridization, fluorescent in situ hybridization, and actinomycin D-DAPI. Here, we show the homeology of P. perezi and P. grafi somatic karyotypes to other Pelophylax taxa with 2n = 26 and equal contribution of ridibundus and perezi chromosomes in P. grafi which supports F1 hybrid genome constitution as well as a hemiclonal genome inheritance. We show that ridibundus chromosomes have larger regions of interstitial (TTAGGG)n repeats flanking the nucleolus organizing region on chromosome no. 10 and a high quantity of AT pairs in the centromeric regions. In P. perezi, we found species-specific sequences in metaphase chromosomes and marker structures in lampbrush chromosomes. Pericentromeric RrS1 repeat sequence was present in perezi and ridibundus chromosomes, but the blocks were stronger in ridibundus. Various cytogenetic techniques applied to the P-G system provide genome discrimination between ridibundus and perezi chromosomal sets. They could be used in studies of germ-line cells to explain patterns of clonal gametogenesis in P. grafi and broaden the knowledge about reproductive strategies in hybrid animals.

• Klíčová slova
• Pelophylax grafi, Pelophylax perezi, comparative genomic hybridization, fluorescent in situ hybridization, hybridogenesis, karyotype,
• MeSH
• centromera * genetika   MeSH
• hybridizace in situ fluorescenční MeSH
• karyotypizace MeSH
• Ranidae * genetika   MeSH
• srovnávací genomová hybridizace MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This study aims to determine the bacterial flora on the skin surface of the juvenile forms of Pelophylax ridibundus inhabiting three different altitudes and examine potential correlations between bacterial diversity, ecological location, and factors. It was attempted to characterize thirty-two bacteria isolated from the Melet River, Sülük Lake, and Çambaşı Pond through combined biochemical and molecular methods. Canonical correspondence analysis showed that the most important ecological factors for microorganisms to settle on frog skin were determined as water conductivity and dissolved oxygen amount. The most frequently isolated bacteria belonged to the genera Erwinia and Pseudomonas. Altitude positively affected Exiguobacterium. This first report of skin cultivable bacteria from P. ridibundus juvenile forms natural population improves our knowledge of amphibian skin bacterial flora. This study contributes to a better understanding of their ecology and how this species has survived in an environment modulated by altitude.

• Klíčová slova
• 16S rDNA, CCA, Environmental bacteria, Marsh frog, Skin flora,
• MeSH
• Bacteria * MeSH
• kůže MeSH
• Ranidae * mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Amphibian species have the largest genome size enriched with repetitive sequences and relatively similar karyotypes. Moreover, many amphibian species frequently hybridize causing nuclear and mitochondrial genome introgressions. In addition, hybridization in some amphibian species may lead to clonality and polyploidization. All such events were found in water frogs from the genus Pelophylax. Among the species within the genus Pelophylax, P. esculentus complex is the most widely distributed and well-studied. This complex includes two parental species, P. ridibundus and P. lessonae, and their hybrids, P. esculentus, reproducing hemiclonally. Parental species and their hybrids have similar but slightly polymorphic karyotypes, so their precise identification is still required. Here, we have developed a complete set of 13 chromosome painting probes for two parental species allowing the precise identification of all chromosomes. Applying chromosomal painting, we identified homologous chromosomes in both parental species and orthologous chromosomes in their diploid hemiclonal hybrids. Comparative painting did not reveal interchromosomal exchanges between the studied water frog species and their hybrids. Using cross-specific chromosome painting, we detected unequal distribution of the signals along chromosomes suggesting the presence of species-specific tandem repeats. Application of chromosomal paints to the karyotypes of hybrids revealed differences in the intensity of staining for P. ridibundus and P. lessonae chromosomes. Thus, both parental genomes have a divergence in unique sequences. Obtained chromosome probes may serve as a powerful tool to unravel chromosomal evolution in phylogenetically related species, identify individual chromosomes in different cell types, and investigate the elimination of chromosomes in hybrid water frogs.

• Klíčová slova
• Chromosomal painting, Chromosome evolution, Clonal hybrids, Cytogenetics, Fluorescence in situ hybridization, Pelophylax esculentus complex,
• MeSH
• karyotyp MeSH
• karyotypizace MeSH
• malování chromozomů * MeSH
• Rana esculenta genetika   MeSH
• Ranidae * genetika   MeSH
• žáby genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Proteocephalid tapeworms of frogs of the family Ranidae ('true' frogs) are reviewed with emphasis on their species diversity, host specificity and geographical distribution. New molecular data (nuclear lsrDNA and mitochondrial COI sequences) are presented for tapeworms of four species of ranid frogs in North America, including the poorly known Ophiotaenia saphena Osler, 1931 of Rana clamitans Latreille and R. catesbeiana (Shaw), which is redescribed using new material from Arkansas, USA. Tapeworms of R. sphenocephala (Cope) and R. pipiens Schreber, the latter previously identified as O. saphena, represent another, putative new species, but are not formally described due to insufficient available material. Proteocephalus papuensis Bursey, Goldberg et Kraus, 2008 from Sylvirana supragrisea (Menzies) is transferred to Ophiotaenia La Rue, 1911 as a new combination. After a critical review of the literature, only nine nominal species of Ophiotaenia are recognised as valid, which is in contrast to the large number of ranid frogs (> 440 spp.). The reasons for this striking disparity are briefly discussed, and a key based on morphology is presented for the identification of all species of Ophiotaenia from the Ranidae. Molecular data are available for only two taxa from North America that form a monophyletic group. The relationships among tapeworms of ranid frogs occurring in other zoogeographical regions are not yet known. The taxonomic status of Batrachotaenia Rudin, 1917, which was erected to accommodate proteocephalids from amphibians, is also discussed. To facilitate future studies, a tabulated summary of all 32 species of proteocephalids belonging to three genera reported from amphibians (frogs and salamanders) is presented, with information on their hosts, distribution, and taxonomically important characters, including key measurements.

• Klíčová slova
• Amphibia, Anura, Nearctic region, Onchoproteocephalidea, Ophiotaenia, global diversity, molecular data, morphology, redescription, taxonomy,
• MeSH
• Cestoda * MeSH
• cestodózy * epidemiologie   veterinární   MeSH
• Ranidae MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Geografické názvy
• Severní Amerika MeSH

Amphibians have highly diverse sex-determining modes leading to a notable interest in vertebrate sex determination and sex chromosome evolution. The identification of sex-determining systems in amphibians, however, is often difficult as a vast majority consist of homomorphic sex chromosomes making them hard to distinguish. In this study, we used Diversity Array Technology sequencing (DArTseq) to identify the sex-determining system in the ornate burrowing frog from Australia, Platyplectrum ornatum. We applied DArTseq to 44 individuals, 19 males and 25 females, collected from two locations to develop sex-linked markers. Unexpectedly, these 44 individuals were classified into two distinct population clusters based on our SNP analyses, 36 individuals in cluster 1, and 8 individuals in cluster 2. We then performed sex-linkage analyses separately in each cluster. We identified 35 sex-linked markers from cluster 1, which were all associated with maleness. Therefore, P. ornatum cluster 1 is utilising a male heterogametic (XX/XY) sex-determining system. On the other hand, we identified 210 sex-linked markers from cluster 2, of which 89 were male specific, i.e., identifying XX/XY sex determining system and 111 were female specific, i.e., identifying ZZ/ZW sex determining system, suggesting existence of either male or female heterogametic sex determining system in cluster 2. We also performed cytogenetic analyses in 1 male and 1 female from cluster 1; however, we did not detect any visible differentiation between the X and Y sex chromosomes. We also mapped sex-linked markers from the two clusters against the P. ornatum genome and our comparative analysis indicated that the sex chromosomes in both clusters shared homologies to chromosome 10 (autosome) of Rana temporaria and ZWY sex chromosome of Xenopus tropicalis. Our preliminary data suggest that it is plausible that the cluster 2 has a potential to be either male or female heterogamety in sex determination, requiring further investigation.

• MeSH
• biologické markery MeSH
• lidé MeSH
• pohlavní chromozomy * genetika   MeSH
• Rana temporaria MeSH
• Xenopus MeSH
• žáby * genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Austrálie MeSH
• Názvy látek
• biologické markery MeSH

Parasites might represent a helpful tool in understanding the historical dispersion and phylogeography of their hosts. In order to reveal whether the migration routes and diversification of hosts can be traceable in the genetic structures of their parasites, we investigated the diversity of paramphistomoid trematodes of Pelophylax frogs in 2 geographically distant European regions. Water frogs belonging to the genus Pelophylax represent a striking example of a species with a high variety of ecological adaptations and a rich evolutionary history. The parasites were collected from 2 Balkan endemic species, P. epeiroticus and P. kurtmuelleri, and 2 species in Slovakia, P. esculentus and P. ridibundus. While in Slovakia, Pelophylax frogs harboured 2 species, the diplodiscid Diplodiscus subclavatus and the cladorchiid Opisthodiscus diplodiscoides, only the former was recorded in the south-western Balkans. Remarkably high genetic diversity (16 unique mitochondrial cox1 haplotypes, recognized among 60 novel sequences) was observed in D. subclavatus, and subsequent phylogenetic analyses revealed a strong population-genetic structure associated with geographical distribution. We also evidenced the existence of 2 divergent D. subclavatus cox1 haplogroups in the south-western Balkans, which might be associated with the historical diversification of endemic water frogs in the regional glacial microrefugia.

• Klíčová slova
• Balkan Peninsula, Diplodiscus subclavatus, Opisthodiscus diplodiscoides, Pelophylax, haplotype diversity, population genetics,
• MeSH
• fylogeneze MeSH
• fylogeografie MeSH
• genetická variace MeSH
• paraziti * MeSH
• Ranidae MeSH
• Trematoda * genetika   MeSH
• voda MeSH
• žáby MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda MeSH

BACKGROUND: Hybrid taxa exist in nature, but their fitness can vary greatly. Hybrids are usually thought to have lower viability and survival rate than parental species due to the occurrence of two different genomes and divergent evolution in each species. On the other hand, the hybrid vigour of the F1 generation may give hybrids an advantage in mixed populations where they have to live and compete with parental taxa. Post-zygotic selection with endogenous genetic mechanisms may be a significant evolutionary force in hybrid formation. Here we tested principles of post-zygotic reproductive dynamics in mixed populations of Pelophylax water frogs that would help us understand the origin and maintenance of such systems. METHODS: Within experimental crosses, we combined various diploid Pelophylax genotypes resulting in 211 families. Statistical analysis of progeny was used to measure fertilization success, the rate of embryonic/tadpole mortality and the overall survival of the progeny till the time of metamorphosis. Using Generalized Estimating Equations models and variables defined by a mother/father included in mate pairs, we tested which factor best explains the successful embryonal development. RESULTS: The development of Pelophylax offspring significantly varied in survival rate and morphological malformations. These post-zygotic reproductive dynamics were driven by parental combinations of species pairs. The best values in the proportion of developing eggs, embryos, tadpoles and overall survival showed progeny of homospecific P. lessonae crosses. Total survival rates were relatively similar between L-E and R-E population systems but much lower than homospecific crosses in parental taxa. However, once the early stages passed this period, tadpoles mostly of hybrid hemiclonal origin performed even better than pure P. ridibundus progeny. Hybrid × hybrid crosses showed the highest mortality values. Statistical testing revealed that high mortality affected paternal genetic input. CONCLUSIONS: Combined three water frog taxa and both sexes provided patterns of post-zygotic reproduction dynamics of early development in the widespread population systems in Central Europe. The results further showed high survival rates of hybrid F1s created de novo from parental species despite significant divergence between P. ridibundus and P. lessonae DNA. Potential conservation measures of sexual-asexual systems in natural populations are discussed.

• Klíčová slova
• asexual reproduction, embryogenesis, hemiclonal, hybridogenesis, mortality,
• MeSH
• genomika MeSH
• hybridizace genetická * MeSH
• lidé MeSH
• otcové MeSH
• Ranidae genetika   MeSH
• voda * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda * MeSH

Secondary sympatry amongst sister lineages is strongly associated with genetic and ecological divergence. This pattern suggests that for closely related species to coexist in secondary sympatry, they must accumulate differences in traits that mediate ecological and/or reproductive isolation. Here, we characterized inter- and intraspecific divergence in three giant tree frog species whose distributions stretch across West and Central Africa. Using genome-wide single-nucleotide polymorphism data, we demonstrated that species-level divergence coincides temporally and geographically with a period of large-scale forest fragmentation during the late Pliocene. Our environmental niche models further supported a dynamic history of climatic suitability and stability, and indicated that all three species occupy distinct environmental niches. We found modest morphological differentiation amongst the species with significant divergence in tympanum diameter and male advertisement call. In addition, we confirmed that two species occur in secondary sympatry in Central Africa but found no evidence of hybridization. These patterns support the hypothesis that cycles of genetic exchange and isolation across West and Central Africa have contributed to globally significant biodiversity. Furthermore, divergence in both ecology and reproductive traits appear to have played important roles in maintaining distinct lineages. At the intraspecific level, we found that climatic refugia, precipitation gradients, marine incursions, and potentially riverine barriers generated phylogeographic structure throughout the Pleistocene and into the Holocene. Further studies examining phenotypic divergence and secondary contact amongst these geographically structured populations may demonstrate how smaller scale and more recent biogeographic barriers contribute to regional diversification.

La sympatrie secondaire parmi les espèces sœurs est fortement associée à la divergence génétique et écologique. Ce modèle suggère que pour que des espèces étroitement liées coexistent en sympatrie secondaire, elles doivent accumuler des différences dans les traits qui contribuent à l'isolement écologique ou reproductif. Ici, nous avons caractérisé la divergence inter- et intra-spécifique chez trois espèces de grenouilles arboricoles géantes dont les distributions s'étendent à travers l'Afrique de l'Ouest et Centrale. Avec des données génétiques, nous avons démontré que la divergence au niveau des espèces coïncide temporellement et géographiquement avec une période de fragmentation forestière à la fin du Pliocène. Nos modèles de niches environnementales ont soutenu une histoire dynamique de stabilité climatique, et ont indiqué que les trois espèces occupent des niches environnementales distinctes. Nous avons trouvé une différenciation morphologique modeste parmi les trois espèces mais une divergence significative dans le diamètre du tympan et les cris des mâles. De plus, nous avons confirmé que deux espèces sont présentes en sympatrie secondaire en Afrique Centrale mais n'avons trouvé aucune preuve d'hybridation. Ces résultats soutiennent l'hypothèse que les cycles d'échange génétique et d'isolement à travers l'Afrique de l'Ouest et Centrale ont contribué à une profonde concentration de biodiversité dans la région. De plus, la divergence des traits écologiques et reproducteurs semble avoir joué un rôle important dans le maintien de lignées distinctes. Au niveau intra-spécifique, nous avons constaté que les refuges climatiques, les gradients de précipitation, les incursions marines et potentiellement les barrières fluviales ont généré une structure phylogéographique pendant le Pléistocène et jusqu'à l'Holocène. Des études examinant la divergence phénotypique et le contact secondaire entre ces populations géographiquement structurées pourraient démontrer comment des barrières biogéographiques à échelle plus petite et plus récentes contribuent à la diversification régionale.

• Klíčová slova
• demographic modelling, divergence, ecological niche, land-bridge island, phylogeography, refugia,
• MeSH
• biodiverzita * MeSH
• fylogeneze MeSH
• fylogeografie MeSH
• genetická variace MeSH
• lesy MeSH
• mitochondriální DNA genetika   MeSH
• Ranidae genetika   MeSH
• žáby * genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• střední Afrika MeSH
• Názvy látek
• mitochondriální DNA MeSH

The coexistence of species in a given community depends on the set of species involved and the timing of their interactions. Many native communities are increasingly forced to face both direct and indirect pressures from new alien predators, which, in extreme cases, can lead to the extinction of prey populations. In this study, we examine the dynamics of the ontogeny of common frog (Rana temporaria) tadpoles under different time patterns of an alien predator-the red-eared slider (Trachemys scripta elegans) presence. We found that the tadpoles had a longer larval period and were smaller in size at metamorphosis and lower in body mass when the predator was present in early development than when the tadpoles developed without a predator. The early presence of a predator conspicuously reduced the growth increments of the tadpoles at early development. After the removal of the predator, growth accelerated above the level measured under the conditions of both the late predator and no predator. However, these growth rates did not exceed the growth rates of equally sized tadpoles in the other treatments and therefore were not sufficient to compensate for the growth slowdown in the first part of development. The presence of a predator in late tadpole development influenced neither the time to metamorphosis nor size/body mass at metamorphosis. In conclusion, the predator had the effect on metamorphosis traits only if it was present in the early development of tadpoles.

• MeSH
• biologická proměna MeSH
• larva MeSH
• predátorské chování * MeSH
• Rana temporaria MeSH
• žáby MeSH
• želvy * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH